Lock and nonlock 904 case the same?

The case won't be a problem. It's my understanding that the main differences are in the pump and valve body. The swap has been done often , but I don't know if any specific, individual parts need or don't need to be swapped or modified. My trans people swapped non-lock-up guts into lock-up cases many times for my race cars, which sometimes had the 2.74 low as opposed to the standard 2.45.