I have a quick question I hope someone can answer ASAP.

I bought a set of used beach house sponsons online that haven't shipped yet. The seller said they are from a STXR 1200 and fit the 12f and 15f which all have the same hull. This morning I was looking and the stxr/stx have different part #s, and saw someone say on here they are NOT interchangeable.

Does anyone know what the difference is?