im in the process of buying CTR cams and i wanna know how to to identify them. just in case the guy tries to rip me off

he's talking about cams, not pistons.

anyway the CTR cams are easy to spot, on the end of the Intake Cam, there are two circular grooves, whereas the ITR cams only has one.

http://ff-squad.com/tech/cams/cam_markings.jpg

My bad, Kind of lat when I posted