Combat - Fixed combat sights
Target - Adjustable sights and trigger stop
Sport - Adjustable sights, trigger stop, extended barrel and barrel weight
I said in general because I've seen factory oddities like a combat with trigger stop.
The Sports may also have different grips... especially if in sport groups.
Collectibility would typically be in order of Sport Group, Sport, Target, Combat... with .45 at a premium to 9 mm.