The fake Doom letting Latveria fall to Tyger, is quite possibl. (Though there is that one bit from #25 on Castle Doom falling before foreign missiles in 2060...) But from Tyger's own remark in issue #1 that "Doom died before I was born", the genuine thing was absent from Latveria far before that ever happened. And I find it hard to imagine the real Doom leaving Latveria alone for so long, even if it was to rule from the shadows.
But yeah, it's not really necessary to confirm or deny whether it was the real Doom.