442 nickel; What's the pin for?

[shooter7]

The model 442 made in the mid 1990's in nickel, has a pin behind the cylinder recoil shield. What is this pin for, and are there any other j frames that have this pin?
I passed on a good deal one time on this gun, because the nickel had flaked a little in this area on the gun, and I, without my glasses, thought it was a "pit" or corrosion spot.

[Tyrod]

That's a firing pin retaining pin. Seems like that method was in use early-mid 90s. Maybe late 80s. I have a 1994 442 with it.