So, not all Lionel TMCC are upgradeable to Cruise "M" kit.

Lionel did not make that board. While is uses some Lionel boards the motor driver was made by TAS, a different company. In addition 3rd Rail and Atlas used TAS until they closed down.

Pete

If you need more information on the TAS stuff, the Reference Materials pinned thread has all the TAS manuals upload for your enjoyment.

The boards all have Lionel on them?

Not all the boards, just the three plug-in boards.  The motherboard is the TAS part, it's the motor driver and interconnection board.  TAS made a lot of different stuff, they also had a cruise version, and even a drop-in cruise like the Cruise Commander M.

correct, my error. Looking at them in the light today, I see only the 3 are Lionel.

TAS purchased the TMCC and the RailSounds boards from Lionel and then they made the motor driver boards, smoke units, etc.

When Lionel licensed TMCC to third parties I believe it was requirement that they use Lionel radio and audio boards though I recall some of Jon Z's early offerings included an integrated radio/motor driver board, not unlike current Legacy boards. I have one in a Beep that pre dated the Beep Commander.

Pete