There was a recall.

It was on the cylinder due to substandard material of one lot of stock that was let in. I believe if you have the box, it was marked with an "M" in red, IIRC (this is going by memory from 10 years ago, so don't read this as gospel...).

I've got one I got new in 1985, and I shot some really heavy handloads in it (such that I would never shoot today), so I never sent mine in, because if it lived through those handloads, it will live through any sane handload or factory load...

You can call S&W's 800 number and give them the serial number, or e-mail them. They may know if it was already checked. If it has never been checked, they cannot tell you by the serial number if it is OK or not. You will HAVE to send it in to them.

The other issue with these is that they are pre-endurance package guns. This means they are susceptible to early wear symptoms (such as end-shake and cylinder unlocking/rotating backwards) and sometimes even the trigger and hammer pins break off. These are all issues that can be fixed at the factory. In my experience they show up rarely, and only if the gun is shot A LOT with HEAVY loads.

I shoot mine almost exclusively with mid-range loads with lead bullets now, so it should last forever without further worries. I have a later 629-4 for heavy loads now.