I'd buy a locking block kit from Beretta and keep it on hand as a just in case sort of thing. Unless something is really wrong with the gun or block, even an old generation locking block should last several thousand rounds so, if it were my gun, I wouldn't replace the block immediately.
By the way, looking at the locking block and the area on the frame where the plunger from the locking block hits it can tell you about how much use the gun has seen. The locking block ears will "polish" from wear where they contact the slide. Also, you can see the mark on the frame where the plunger hits it and the wear to that area can give you some idea of how much the gun has been shot.
While you're buying the kit, you might take a look at some of the other extras Beretta offers. They have a number of neat "custom" parts and kits for the 92. For example, the oversized magazine release is a simple "upgrade". I wouldn't recommend it for duty use since I think it might increase the chances of accidentally dropping a mag, but for range use or competition, it's nice.
The hex-key grip screws are a nice visual upgrade, IMO.
They also have some really expensive kits like their Xtreme-S action kit. I'm curious about how much improvement it provides, but not curious enough to shell out $200. But it's there if you want it, along with a lot of other goodies.
Also, I check their stock from time to time and they regularly add new items which gives me a nice warm fuzzy feeling that Beretta intends to support for the 92/96 pistols for awhile.
