If a piston states it is for stock compression, does that also mean it is for the standerd bore?

 

I don't think so but wait for someone else to chime in

 

you can have stock compression oversized pistons.

 

No. It sounds to me like it implies that it's stock... mostly because if they're oversized, that's a selling point and they will state that. But based only on what you said, you cannot say for sure what size they are. Like the other guy said, you can have oversized pistons but still have the same CR.