That's how I took it -- or at least the entire Green/Johnson run. It's a nice way to fold it into continuity, explaining why its in some weird continuity that exactly parallels our own except where they don't want it to -- without shoehorning it or leaving it in La La Limbo.

Coincidentally, I hated it when O'Neil pulled that stunt with the Super-Sons. But then, they had multiple Earths they could actually use back then.