If you wanted a toy, you went into a toy shop (such as the famous "Child's World" in Moscow) or to the toy stand in an UniverMag, or, you looked for something in thematic magazines. The toys you bought in a supermarket contained information on the factory it was made in and, sometimes, a credit to the artist behind it. I don't know if there are any English language scholars specifically writing about the Soviet toy industry but on the Russian language internet there are numerous websites (for instance www.igrushki-ussr.ru) with people sharing their memories or trying to catalogue (year, factory, artist) their old Soviet toys.