Is there also a mark on the frame flat of your gun which has the appearence of XX. This is a very common mark on 16 & 20 ga Lefevers & normally denotes a gun with a slightly narrower bar to the frame. I do not believe it has ever been determined for certain what the 2 denotes. Some have assumed it was for a heavier frame, but I have a 16ga SN H 62,596 which has both the XX & a 2 on it. It does have the narrower width across the bar.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra