I bought a very good condition Remington Wingmaster with two barrels, one long (28 inch)and one short (18.5). The long barrel was the original barrel and has a matching serial number to the receiver, and the short 18.5 barrel is a newer style barrel that the last owner bought later on to make the gun more universal for hunting and self defense.
Also a magazine extension was added to give the gun 2 more extra rounds.
Looking at the barrel and the AWW marking my guess is that this is a first year production 870 and made in March 1950.
Also the serial number is 137XX and I figure that’s a big indicator the gun is also pretty old.
Is my guess on the year correct ?

I would say yes, 1950 is correct

Congratulations on another beautiful shotgun.

Beautiful condition Wingmaster from the 50's.

I have a 50's made Wingmaster with the same handguard.  But yours is in much better condition.

The action should be buttery smooth.

Whenever I take new shooters to try out trap shooting, I always hand them my Wingmaster.  Young dudes love the pump action and will reach for it over a Remy 1100.  I guess they seen too many movies.

Is it my imagination or is the mag extension flexing down, away from the barrel?
Maybe that aftermarket clamp is too large, forcing the barrel and extension apart?

Or maybe I'm just seeing things.

Very nice 870 by the way.

It looks fine in real life.
It must be an optical illusion that it’s pointed downward in some of the photos, however in this photo it’s level.
And by the way it now wears an Original Remington barrel clamp and not an after market one.