Yea, but the Shield and SDVE is still going to be sold there. Does that mean they're going to micro stamp those and not the other M&Ps?
If I had to guess, I'd suspect it's because the Shield and SDVE lines have already been certified and approved to be on the state roster in their current form. If so, they won't be considered "new" models when their certifications expire, and could then be renewed (before expiration) without having to incorporate microstamping technology.
In other words, they won't be needing/receiving the further "performance enhancements" slated for the older M&P models as they reach their expiration dates on the current roster.
If the safety testing rules mean that adding such performance enhancements to the rest of the M&P line makes them "new models", then it wouldn't be surprising that they're going to end up falling under the microstamping requirement for new pistols.
For those of you who weren't keeping up with this law that's been on the books for a few years, here's some info from last year. This is a link to the documents contained in the state DOJ Certification of Microstamping Technology Notice from May last year.
http://oag.ca.gov/sites/all/files/agweb/pdfs/firearms/infobuls/2013-BOF-03.pdf
Note the language ...
"Semiautomatic pistols already listed on the Roster of Handguns Certified for Sale in California will remain on the roster and need not incorporate the microstamping technology ..." and
"... a semiautomatic pistol not already listed ..."
Even some news articles I've browsed to recheck include blurbs (toward the end) that this new law won't affect
existing pistols on the state roster.
This all may still change as recent legal challenges work their way through the courts (being supported by S&W, among others, it seems), but it still looks like it affects
new model pistols being added to the roster,
and, it seems,
existing models that may have received modifications making them different from when they originally received their certification to be accepted on the list ... and which are going to have their existing certifications expire in the near future (from the end of this month to Aug, if I recall the roster dates last time I looked at them).
Not much choice but to wait and see what happens with the legal challenges.