In fact, the Toyco in question was and still is a Japanese company. This is the actual website http://www.toyco.co.jp/company.html.
The original Astro Magnum clearly shows a Toyco head office address in Tokyo on the packaging, and both the original 'laser gun' packed version, and the latter 'robot' packed version were manufactured in Japan (as per the box and stamping on the battery cover). The trademark is of course, unmistakable.
The Astro Magnum toys were manufactured in Japan and distributed by Toyco. The original realease bore a maker's mark, 'Toyco', with no copyright notice.
The figure was then licensed to other parties. As we know, Shockwave was initially released to western markets as a Transformer by Hasbro prior to Christmas 1984, and was part of the Japanese toyline in 1985. Radio Shack, a subsidiary of Tandy, also released a version known as Galactic Man at roughly the same time internationally through its network of stores. When the figures were licensed to Hasbro and Tandy, (as well as other US toy companies), it appears that manufacture was off-shored to Seoul, to a manufacturing partner called Intecs, Ltd.. Both Shockwave and Galactic Man are stamped 'Toyco, © 1983' and 'MADE IN KOREA', and there are references to being made in Korea on the packaging and papers included. However only on the back of G1 Shockwave is it clear that the manufacturing partner Intecs, Ltd..
I can only surmise that the manufacturing was moved to Korea for reasons of production capacity or economics. No doubt the contracts with American companies called for high volume at low cost. It is typical that copyrights are sought for legal reasons when a figure is planned to be distributed outside of Japan. Domestic release toys often featured a maker's mark but not a copyright notice. So it's apparent to me that the appearance of the copyright notice on the toy indicates the involvement of non-Japanese market companies.
It becomes unclear at this point, who is the licensor to Hasbro and Radio Shack (*see next paragraph), as while Toyco is responsible for the design and manufacture of the original toy, and have acknowledged it here in a roundabout way, there are questions as to what parties have rights to produce and market the toy today, even if the mold's whereabouts were known. Paperwork only refers to Intecs and never Toyco, but Toyco remains the maker's mark on the figures. (Fast forward to today - Hasbro of course would have strong interests in the intellectual property and likeness of Shockwave, though it does not have exclusive rights to the Toyco-G1 toy itself. Hasbro/Takara continues to make toys in the likeness of Shockwave today. And of course the mold appears to be missing.)
*There is a little know variant that has been described (possibly erroneously) as a knock-off called '4 Changeable Spark Man'. It looks like an off-brand Galactic Man, however like G1 Shockwave, it bears the Intecs mark on the packaging, '© 1983 Intecs Ltd.' and is made in Korea. It also features the Japanese patent registration number as seen on the original Toyco Astro Magnum, as well as patent pending application numbers for other regions: UK/HK, Taiwan, Korea, and USA. (These are not searchable today in patent databases as they are not the the same as the published patent numbers.) This is the key detail that suggests the figure may be a legitimate figure. I believe if I were to find a specimen, it would be a Toyco marked figure. It looks identical to Galactic Man, and has the same foam packaging. It appears that Intecs may have (a) registered copyright on the mold (as a good partner), or (b) was acting as a licensor and/or supplying the figure in grey-market off-brand packaging, (c) actually legally acquired the rights from Toyco to license the figure and was the primary licensor for all figures produced in Korea (being Shockwave and Galactic Man.)
A further knock-off figure called 'Electronic Magnum' looks to have been copyrighted in 1984 by an American entity called S.R. Mickelberg Co., Inc. in PA, USA, who owned the Royal Condor trademark from 1981 to 2005. It appears to be identical to the Spark Man figure, down to the foam and packaging format.
This may offer a clue into the ambiguity of ownership. Several parties appear to have asserted their rights to the toy. Unfortunately I can not confirm anything until I hold specimens in my hands and perform detailed mold analysis to determine lineage.
During the 80s Japanese toy companies generally made toys in Japan, for Japan. The Takara-developed Transformer toys were all initially made in Japan, and in accordance with the operational and financial realities of distributing the toyline internationally in partnership with Hasbro, certain toys were produced in countries such as Korea, Thailand, Taiwan, Macau, France, and eventually predominantly in China and recently Vietnam. The idea that Toyco is Korean seems to be the result of flawed deduction supported (understandably) by a single piece of erroneous data - the website.
However, what often isn't discussed is the manufacturing partners that are often responsible for mold tooling and/or manufacture, done on behalf of the toy designer. This adds complexity to understanding the history of some figures. The figure known as G1 Jetfire is one such example, conceived by the legendary Shoji Kawamori and first sold by Takatoku Toys in Japan as the Macross 1/55 Valkyrie, the figure was actually designed, and manufactured by Matsushiro (patented by Yukimitsu Matsushiro in 1984). The Toybox Mechabot-1 figure and its Hasbro-licensed G1 Omega Supreme, were actually designed and manufactured by Tomy on Toybox's behalf. This only became apparent when after Takara-Tomy's merger in the mid 2000s, it was discovered Tomy still had the molds for Omega Supreme and Sky Lynx.