I have an old Model 11 with an early serial #. This belonged to my Grandfather, who was a Cmdr in the Navy during WW2.
The gun features an anchor mark on the barrel.
A Remington Model 11 shotgun with an anchor stamp on the barrel, often accompanied by "REP" (Remington Proof), indicates a World War Il-era production, specifically used for military-contracted riot guns or training weapons.