While I get where you're coming from with that, I think you're overstating the issue. UPCs today may not be what they were 20 years ago (I'm not sure about this, just taking your word on it). But we have evidence of what UPCs did mean back then. In a word, nothing.
And bringing up Atari opens a can of worms that wasn't really an issue as far as Sonic goes. Yes, the days before official licensing schemes are in a league of their own. And, let's be honest, they aren't without their own little quirks. If Air Raid were made today and distributed in the same quantity nobody would give a shit. It's just another example of something the gaming community as a whole seems to suffer from in most respects, namely
older is better.
But at least with Atari people are up front about what they're cataloging. Everybody
knows that there was little in the way of "official" games. And if a game plays on the Atari and is older than a brand new homebrew then it's welcomed in along with everything else. It's at least internally consistent in that respect. Meanwhile, more modern systems, SMS included, the lists are written with more clarity. The line between "official" releases vs. unlicensed vs. homebrew is
much better defined. So we should at least expect that same level of clarity with regard to Sonic and other games/merchandise in a similar situation.
And we're not necessarily just talking about games released yesterday. Sonic came out in 1991. Radiant Silvergun was 1998. That's not exactly a long time. I don't think there was any revolution going on between the tail end of the SMS and the twilight years of the Saturn. I posted how UPC codes don't really matter, like, at all for the GBA. And it goes back at least as far as the NES. The European Super Mario Bros. has the same UPC as the American one. So if Sega slapped a new UPC on Sonic it really doesn't seem like evidence they were doing it to create an American version. And for Radiant Silvergun to
not have a new UPC apparently doesn't exempt it from possibly being an "American release" in that case. I just don't see the smoking gun.