Looks like sometime in 1985. Glad you had a chance to shoot some double-action. Once you get used to it -- single-action feels weird.

I rarely shoot 200 rounds at a time, so my cleaning takes just minutes. The chambers and the barrel I clean with solvent and a brush and cleaning patches. In the places the black soot collects around the forcing cone and the recoil shield I take a fine bronze brush and brush through the accummulation. The rest of the gun's exterior I can just wipe with a rag with some gun cleaning solvent on it and it looks fine. After that I wipe it with a alcohol pad and then put a light coat of wax on it.