Beautiful Model 31. Congratulations!!
I see the date code on the barrel is RE, R = November E = 1936. I have a similar gun, but not as nice, with barrel date code AE A = March E = 1936 --
509185 03.JPG
Gotta ask, what makes you think your gun is a B "Special" Grade? I don't see it marked B Grade --
B-Grade marking.jpg