Maybe everyone should read all the postings in this message.
The 14 piece set stainless fender trim (if that is what is being discussed) was a GM factory option for Advance-Design Panel Truck and Canopy Express. The same size fit the 1/2 ton and 1 ton trucks (the front and rear fenders were the same).
These parts might have been installed by owners and/or dealers on other models of trucks.
Even if these parts are now found on a 3/4 ton pickup, I do not think the 1/2 ton and 3/4 pickups have different sized fenders.