(Traitor!...ah-hem...)
Since the Gato was the Cadillac of submarines (OK, not when compared to a XXI, etc., but most boats), I would expect a modeler to embrace it in 1:72! Especially you, mate! There are heaps of good accessories (some from AMP!) for the 1:72.
Gatos (and the later Balao and Tench versions) had the BEST Torpedo Data Computer (could handle tracking as well as basic calcs, was better than the Kriegsmarine TDC and waaay better than the IJN), 10 torp tubes (6/4), lots of radar evolution, refrigeration and freezer for food, air con for fighting condensation (electrical circuit priority, not crew, but they enjoyed it too)...the list goes on and on!
OH, you mean exterior model accessories. In 1:144, I don't know of much. Buy a 1:72!