poulan 36cc 2050 2051 42cc

I have a few different poulan saws. Some say 36cc on the epa sticker and some say 42cc. I want to replace the piston and cylinder in a poulan 2050 that has a 36cc sticker on it but the only kits I can find are 41.1mm. Am I missing something? Wouldnt that be 42cc and shouldn't the epa sticker...