Agree, if just superficial rust, clean it up, prime and paint.
Also, the Caterpillar 3126 same with two choices for pans/oil capacity.
Because you mention rust, I ASSUME you have the stamped steel (shallow) pan, not the deep aluminum pan. Safari used the deep pan on many of the earlier engines.
Ex: 2003 Alpine 38FDDS. Ex: 1997 Safari Sahara. Ex: 1993 Foretravel U240