We should be able to change clothes in the film, it would still be film accurate to be honest. We should be at to choose what clothes, face/body model and mask we want to use, and if we want to use him unmasked we should,
In Part 2 Jason unmasked was likely a dream, in the beginning of 3 we see that Jason in his part 2 clothes at the beginning of the movie in the store, so if we want to use part 3 with the part 2 clothes we should
Also for alot of part 3 he's unmasked in the movie, so if we want to use him unmasked from the get go.
Also part 3 unmasked could be considered a dream, as part 4 was intended to look like the accurate adult version of Jason, so if we want to use the previous movie masks and clothes on him we should.
We should be able to mix and match the masks, clothes and models