Welcome to the forum!

What you have there is a real workhorse of a revolver, made from 1970 to 2004.

The 64 was stainless steel, and offered in 2",3" and 4"barrel length, in a tapered or heavy barrel.Variations had round or square butt shapes.

From my reference book, it appears yours was made in 1973 or 1974.

I owned an early one with a tapered 4" barrel, that had the flash chromed hammer and trigger.

The 64's were very popular service revolvers w/ police departments nationwide.