I would assume there is a real 12P (since there is a real 12Z), but I didn't mention anything about such a model in my post. Here is an
ad for a 12Z. The stock bezel for the 12Z in the linked ad looks like the one on my old 6Z bezel (completely smooth without even the vertical knurling lines).
The stock TH for the 12ZM/12PM was supposedly the T-62, also known as the threaded rim TurboHead (TRTH). I have two 12ZMs with TRTHs. Some 12ZMs and 12PMs apparently came from SF with the SRTH, perhaps based on available parts. I have one of these as well. Others SRTH-equipped models probably came from Lagger Pro.
If the OP's light is a 12Z, the tailcap should say so. If it is a 12ZM, that should be indicated. Obviously, one can easily convert a 12Z into a 12ZM by simply swapping the bezel. Whether that would matter to a buyer might depend on the price and expectation for authenticity.