If you replace a piston with an OEM piston should you change the wrist pin also?

I got a 90 Honda CR125 and I got a good understanding of engines but I replaced the piston on this little honda 125 with a OEM piston and its machined a diffrent way and the wrist pin is a bit loose and doesn't touch the retaining clips so its shorter inside the piston than the old one...any ideas?@45 Cal, sigh no pin came with the piston and on top of that it appears there are 2 types of pistons, OEM, for the same model bike :/