Question on Top End

This is the first time i've torn down my top end on ’03 CR250 (bought it 9 months ago), so i got a few questions. and i'm goin off what the service manual said, so i hope it's right.

it says the recommended piston ring gap should be .4 -.55mm with a service limit of .65mm. it says to take them off the piston, and push them an inch into the bottom of the cylinder and measure the ring gap. my question is, what does it mean if it's less that the recommended gap? I measured mine, and there around .175mm. does that mean I need to replace them, or did the guy that owned it before me put them in wrong, or can I just file them down and be good?

Also, the manual says that the piston and cylinder should have either an A or B on them. I looked, the cylinder has an A, but the piston doesn’t have either, just some numbers. So I’m guessin it’s aftermarket, is there a way to tell what kind it is?

Thanks fellas!!!

I found out i have a wiseco piston std. and i was lookin on their site, cause i read that forged pistons have different specs than cast/stock. and i found what the ring gap is pose to be. on top ring is 0.265mm and the bottom is 0.33147mm. that is still over what mine are at now, but still a lot smaller than the oem at .40-.55mm.

so since it's forged, does any one know the other specs for the wiseco piston? like the cylinder to piston clearance, and the piston o.d.?

Thanks!