Thanks for the reply,

I have removed the front stock and removed the barrels, the only
flat I found is a small strip between the barrels. I did find 3
markes that looked intentional, 3 lines fanned out on one barrel and the number 1521 on the flat strip just in front of the lug of steel that the front stock is held on with. The front stock
is held on with a tapered square pin (the shape of a old nail but wider)