piston ring identification where to find a,b,or c?

[one4boost99gst]

I am rebuilding my 99 Gst. This being one of a few dsm builds I have owned, I do not know how this has slipped my mind and I apologize in advance if this question has been answered many times already. I have forgotten where to find the identification mark a, b, or c on the piston to order piston rings from Mitsubishi. I have tried to locate it by using emory cloth or a light wire wheel. The pistons of course are stock 99 4g63 (63dTF1) pistons. please help thank you...

 

[one4boost99gst]

I figured I had some improper information, After checking with a different Mitsubishi dealer, they told me that only if you are replacing a piston, do they need to know if it is a, b, or c, which is what I recalled from previous builds, the oem rings are the same for all three piston types..a, b, or c.. just wanted to clarify that so nobody else gets confused if this issue comes up.