I ran the update check on Monday, after seeing a few Tweets about this. My phone actually did get the update, and here's the screenshot as proof:
Attachment 233288
Installing it took an eternity, but it worked, and I'm now on OS 10.2.0.1803 (a.k.a. "Software Release 10.2.0.429").
For some reason, people seem to think posting their A/S/L makes a difference. I'm not really sure why. But my actual device is an unlocked STL100-3 (red, from the "LE" program), and has never been on any network other than T-Mobile US.
Oh, and yes, the WiFi calling app is saying "SIM not detected". However, I refuse to actually use that feature until they make it stop posting notifications every damn time my phone gains or loses WiFi coverage.
My fear in all this, of course, is that T-Mobile will use it as an excuse to drag their feet an extra three months on a 10.2.1 update. I sure hope not, but anything's possible.