I came across this on a trade and not really sure too much about it. When I got it, it came in a green hard plastic case with 2 barrels. I looked up the date off the stamped barrel which was W D T 35. Any useful insight would be great.

the "W" is the final inspection mark for the barrel.
the "D" indicates September
Now, the Remington model 1100 did not exist before 1963.........
so the "T" indicates 1970 or 1999;
IF your serial number on the side of the receiver begins with the letter "L" then it is a 1970
IF your serial number on the side of the receiver begins with the letter "R" then it is a 1999
the "35" is the final assemble station where your gun was finished.
Since you state that is comes in a "green plastic case" that is another clue to the gun being a late 90's model as that style case did not exist prior.

Welcome to the Remington Owners Forum BK !!

Post a few pictures of that vintage shotgun...