After some confusion even from the Cat parts guy with ordering a new water pump, I thought I'd post the part numbers in case it would save anyone else some time and trouble.
The water pump for a 3116, SN 9GKXXXXX with transmission cooler, is 126-5918. Reman is 10R-9394.
The WP seals are 2M-4453 and 7F-8267. They were not included.