RETDOE...looks like they got you a first year of production probably late 1964 vintage gun (S prefix)...and congratulations on your successful move to retirement.

The matching numbers on the frame are the assembly numbers.

If you are not a .41 shooter or reloader I would suggest some of the HSM ammo from Midway...

HSM Cowboy Action Ammo 41 Remington Mag 210 Grain Hard Cast Lead

It duplicates the original .41 POLICE load that Remington and Winchester marketed with a 210 grain bullet at 950 fps from a 4" barrel.

Some more reading if you like the .41...

.41 Magnum / 41 Special Load Data Center


May it not be your last .41...welcome to the forums and welcome to The Cult...

Bob