250-500cc Correct Piston Size?

I have a 2002 Husqvarna CR 250 and am about to rebuild the top end. I was researching what the piston size should be, since the bikes have a variance in bore size. Nikasil? I found what I believe to be a C somewhere near the reed area and want to make sure that it is indeed my piston size.
Here are the pictures I've taken of it. Any advice would be greatly appreciated.

I would suggest to disassemble and measure the bore before getting a piston so you can match the clearance well.

Regards.

there should be a letter on the piston crown

+1 internal mic gauge and go from there.

Thanks fellas. Any idea about the tightening torques for the top end rebuild? I found torque specs in the manual, but there is no diagram matching parts with torque and the part description is really vague.

Think on my 360 the head bolts are 17-20nm (i think) thats the six around the top of the head, do front one two rear two front one back like how you would draw a star if that makes sence.
Also the clyinder to crank case ones are diagonal. From each other these are studs so more pressure can be put on them probably read 25-28nm ish not sure not near any manual.
What description are you stuck on?

I think I've got it figured out. I must have just been looking over the torques. I found the cylinder head nuts and cylinder nut torque specs in my manual. I also called the local Husqvarna dealer today and they confirmed what size piston I should order. Thanks for the input!