You're welcome.
Yep, it was interesting that the machined strikers were sometimes experiencing failure at the recessed spot at the base of the head, and that when the design was changed they went to MIM to make the new versions. Of course, the new design makes for pretty much a straight shaft, which seems like a stronger design, with relief for the keeper and spring compression.
The first revised striker assembly I received was for a .45, which is the one pictured. Oddly enough, it didn't seem to be a MIM part, but appears as though it was also a machined part. After talking with someone at S&W about the early .45 striker revisions, it seems possible they were a transition part being made (new design, but still machined) before the changeover to MIM. The revised .40 striker assembly I received was very obviously a MIM part.
You can see at the rear of the early .45 striker revision that there isn't any sign of the usual MIM production method.
Another apparent change in the new design is how the sharp corner at the foot of the striker was changed to a more curved/radiused angle, which ought to make for less potential for a stress riser at that spot.