The chambers would be 2 9/16" and that was changed in the late 1930's to early 1940's. I myself have never seen a stamp for choke but anything is possible with these guns.
Many people have had these guns passed on down to them and did not realize that both the 20 ga. and 16 ga. were short chambered and did shoot 2 3/4" shells from them. Some will say that it does not increase the pressure much but why increase it more on these old guns. The side lock L.C. Smith takes a bad rap for cracks behind the locks and most of it especially the 12 ga. is from shooting modern 2 3/4" magnums causing undue stress on the wood.