Very good point, cthulhu77, you've got it right. If you want to do what appears in the movie, use Balao as a base.
BUT, if you want it historically accurate, you have to remember, that it's time line was early '42. In that case, you'd stay with the kit sail and early war armament. Or, possibly, even go for a pre-war sail, as on the Trumpeter Kit.
But, most of all, remember, this is your model. Do it your way. The rest of us are just kibitzing.
Mike K.