David said
my 20 gauge  shows  3 IN  stamped in after the  2 3/4 :   Its looks like someone just put it on

picture shows it and I want to know if its a factory stamp or just someone playing game..?   DAVE  

David,

What picture? 

Based on your description, my educated guess is that somebody other than Winchester reamed the chamber and remarked it.  Too bad, as that will negatively reduce the value of the gun by a substantial amount.

Bert