I got the 2 pack for Christmas, and the back of the package says that Ghostbusters is fullscreen but that Ghostbusters 2 is widescreen. Is that correct?

No, both are widescreen, it is a mis-print

agreed...this was a major panic earlier in the year, but was debunked

Yep, both widescreen.

I think they've since fixed the mistake on later boxes, as mine says Widescreen for both.