I sort of got into this type of question for a different reason a while back.
{edit, after re-reading the original post and Rick's reply, I suspect your best bet is for moving the mechanicals from the non-TMCC switch to the TMCC one. Feel free to ignore my disertation below on why swapping the command board into the non-command switch may not work. I see now that's not what you really were asking, unfortunately I realized my error after typing the below. }
I had a TMCC switch that the TMCC board failed (or at least that's the symptom, as it works fine in all other respects, just flaky with TMCC).
I asked Lionel about replacement command boards (at that time they were not available, but they acknowledged the need).
During the conversation I mentioned that I would understand if they needed the old board back in a swap, as I could understand them not wanting to sell command boards separately and have folks making their own TMCC switches from regular remote switches (since wheteher we agree or not, that could compete against the TMCC enabled switch sales).
At that time, it was suggested to me that the main board for the switch control is not the same for the TMCC and Remote versions. I looked at the board pretty closely and did note that there was a different transistor style (case was I want to say TO-92 for one (black plastic, half cylinder shape) and the other might have been something that looked more like TO-3 style (metal can, mostly round with a lip near the leads).
Note I did not go as far as to actually look up part numbers, specs, etc.(which is why I am loosely describing the physical characteristics), I just noted this one obvious physical difference.
My point is, if what Lionel told me was correct, even though the port for hooking in the TMCC board may be on the non-TMCC switch main board, it may not work when you move the command board over.
Or everything might be fine. . Just thougt this story might be worth sharing. Be sure to let us know how it works out (with follow up after you've had it in operation for a while).
-Dave