I have a 64-2, 2", made in '72. Is this a bull or a tapered barrel? Hard for me to tell given that the barrel is so short but it looks like a definite taper to me.
S&W eliminated the pencil barrel on the Model 10 in 1995-96 time frame in the midst of the 10-10 series. The Model 64 was introduced in 1970 with a tapered barrel, and in 1972 they introduced the heavy barrel with the 64-1 series. In 1991 they offered ONLY the 3 inch heavy barrel.
I think you're mistaken. Heavy barrels were around way before 1995. I believe the first generation 10 with a heavy barrel was the 10-6. I know that NYC cops had the model 10, and they were heavy barrels in the early 80's.