Just moving this over from another topic:
I meant to clear this up in the original finger discussion but forgot.
There aren’t two different universes; Greg has said before that every rendition of the characters, be it sets, movies, novels, etc. is just an “artistic representation” of their “true” appearances, which we can never truly see.
The book forms and set forms aren’t alternate universe representations of each other, they are just different “approximations” of the character’s one “true” form.