The SN for the K-38 is K218765, and for the M&P 542462. All numbers match on each one.

The stocks on the M&P have some kind of spacer between the stock and the frame, about 3/16th of an inch thick. There was also a t-grip.

I took the grips off the K-38 and there was no SN, only a "K" in sharpie on each side.

I'm going to get each lettered.

Thanks for the information.