Effective with Serial # 9S5001 the Cat part # is 4F7956. The same belt is listed on 4 different arrangements.
Source: Form 30240, D 315 Engine Parts Catalog. Serial #' 9S5001 - Up
I am presuming you are referring to a D315 Engine.
If that is the original power unit, it was probably equipped with the blower fan group to push that hot air out of the house. That group only affects the fan blades and not the belt.