If it is side-by-side, probably Stevens.
Sold by Sears Roebuck. Probably manufactured by Stevens.
Yes.
50-150 USD
From what I could find your gun is made by Winchester. It should say it on your gun somewhere though.
50-150 USD or so
No
1966 to 1988
"Your" Winchester Model 21 Double Barrel Shotgun was manufactured in 1933, giving it an age of 77 years, as of 2010.
Hunter Arms Company, Fulton, New York
when did the make the smithsonian double barrel shotgun
What is the value of a Beebe arms double barrel shotgun?
Most likely Stevens they did make a model #5100