hi Gary (again) 

Yes, some of the subs suffered severall updates in sails, weaponry and also different Measures applied.
There is also the difference of the flood holes / Limber holes, which were representative of the shipyard that build it, but also some modifications ordered by the CO while on duty (enlarging the holes so that it would submerge faster). 
Another situation is the Gato / Balao Class difference: for us modelers it can be made with the same hull*, since - appart from the above mentioned differences even in subs from the same class - the main difference were thicker pressure hull, different machinery, different electronics. So with some work any of the Gato/Balao subs can be made using this as a base.
Good references are needed, of course - I can give you a list if needed.
BTW, of the US WWII submarine force, 52 were lost in combat
Skipper
* it's what we have been doing for decades with the Revell Flasher/Lionfish model 
