Here's my RSS5, same vintage (S/N 108137). Some interesting info about these.... Before the convertibles came out, the Single Sixes had a .222" bore diameter vs later production with a .224" bore to accommodate 22 Mags. This OM will probably shoot way tighter groups than any S-S with a .224" bore.
The hard rubber grips tend to turn brown if exposed to daylight. It's hard to find a good set of "black" grips for less than $100.