2009 G8 Catalytic Converter- Different Part Numbers?

[Sprinkle]

Hey guys I am hoping to find an answer here as I can't find it anywhere else and even the dealerships couldn't tell me the difference...

I am trying to sell my stock cats from my 2009.5 G8 GT. Part numbers stamped on my cats end in 7817 & 7816. From that same year (I assume before the redesign), there were converters produced with part numbers ending in 1315 & 1316.

What is the difference between what I assume are the 2009 cats (1315 & 1316) and the 2009.5 (7817 & 7816) cats?

Everyone interested in buying them only want the 1315 & 1316 cats but NO ONE can tell me what the design difference between these 2 types of cats are...

Pictures attached are what I could find from GM Direct & then my actual cats.

[MIEngineer]

RPO Code between them is different.

09 & 09.5 I imagine with the additional changes.

GXP includes the same RPO as 7816/7 and all GXPs are 09.5.