Yes, the armature is supported at both ends by Oilite bushings.
Either one can wear out, but the front one might wear faster. If either (or both) are worn badly enough, the armature starts rubbing on the pole pieces and the resulting friction robs power from the motor. There is a very strong attraction between the two while cranking, so it may rub while cranking even if it doesn't seem to rub just turning by hand.
The problem is quite obvious when you get it apart, though. Both armature and pole piece will be partially ground away.
The bushings aren't hard to replace; but ISTR availability was a problem. Last time I went through this, I had to buy some that weren't the right length from a different source, and cut them down. But that was a long time ago, so it's probably different today.
In the later starter. Isn't there a bronze bushing somewhere near the front that wears out? Not really too familiar with the inner workings.