Help ID a Model 1897 shotgun|Winchester Military Arms|Forum|Winchester Collector

I have a model 97, s/n 924922, with bayonet lug but no heat shield.  It was purchased by my father used at gun/pawn shop in Wash DC in/about 1966.  It was probably in a police station/prison at some time because it has a number 6 painted on the inside of the pistol grip where it would be visible in a gun rack. 

It is a take down model, the 20″ barrel is marked CYL and the left side of the receiver is stamped US with the ordnance bomb.  BBL and receiver S/Ns match.

I haven’t found any reference to production models with a bayonet lug but no heat shield.

Can anyone help with identification? 

Thanks,

John

Cell # 904 803 3683

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