What the heck is Swamp Assault?

[Konan-Barbarian]

He said the new re-released buildings. There should be plenty of those out there.

I hope he didn't mean the brand new buildings, as those will be impossible to find.

Yeah, but re-released buildings need upgrading just as other new buildings do. That is what those extra Gremlin Carpenters are good for.
I'd say too that there are fewer kingdoms with gem purchased re-released buildings than say those with pink temples or bubble baths.