As you can see, I managed to take both TTL200C motors apart. Identical shafts except that the other one is splined and the other one has a keyhole. I'll probably end up using the keyed one after all, but it all depends. I'm once again rethinking my coupling, but more on that when I have something to show.
Also took apart the other one a bit more to reveal a bit more rust. I'll need to get some of it off and put some paint on instead. Also turned the bolts that hold the brush holder to face outward so I can more easily swap whatever I decide to use as finger protection. Everything under the hood must pass the finger test, which means no live parts should be touchable with the UNECE R100 test finger.