If this has been discussed, I've missed that conversation. I made this discovery some time ago and snagged a few pictures to detail it. What I find most interesting is that evidence suggests that S&W did this… and then later elected to abandon it.
What I'll show here are pictures of two different Performance Center 952 pistols.
The dark one is a 952-1 pistol and I had the wood stocks off because a previous owner had butchered the grip screw bushings so you will notice in the picture of the blued 952-1 that the upper grip screw bushing is not in place.
The bushing hole is key to this discussion because it is just to the right of this spot where the microstamping is present.
The Performance Center pistols have the serial number located under the grip and you can see that on the left and the microstamping on the right.
Here is a picture that I zoomed in on so that you can see a better view — indeed, it doesn't look very clear. But it is there for sure:
The last picture is of my 952-2 stainless, a pistol that was made a few years later than the 952-1 that has the microstamping.
Note that I have obscured the last two digits on this one, but the point of the exercise is to show how the microstamping simply does not exist on the later pistol. You will also notice that I did not touch the stock screw bushings on this pistol — this one is mint and there was no need to mess with them and replace anything, so you'll see the hole looks larger on the 952-1 than on this pistol.
I haven't dug in to any of my other S&W pistols made in the early-to-mid 2000's when this 952-1 was made to see if any others have this microstamping. But I did think this might make for interesting forum fodder.
What I'll show here are pictures of two different Performance Center 952 pistols.
The dark one is a 952-1 pistol and I had the wood stocks off because a previous owner had butchered the grip screw bushings so you will notice in the picture of the blued 952-1 that the upper grip screw bushing is not in place.
The bushing hole is key to this discussion because it is just to the right of this spot where the microstamping is present.
The Performance Center pistols have the serial number located under the grip and you can see that on the left and the microstamping on the right.

Here is a picture that I zoomed in on so that you can see a better view — indeed, it doesn't look very clear. But it is there for sure:

The last picture is of my 952-2 stainless, a pistol that was made a few years later than the 952-1 that has the microstamping.

Note that I have obscured the last two digits on this one, but the point of the exercise is to show how the microstamping simply does not exist on the later pistol. You will also notice that I did not touch the stock screw bushings on this pistol — this one is mint and there was no need to mess with them and replace anything, so you'll see the hole looks larger on the 952-1 than on this pistol.
I haven't dug in to any of my other S&W pistols made in the early-to-mid 2000's when this 952-1 was made to see if any others have this microstamping. But I did think this might make for interesting forum fodder.