The jaws should open and close easily. I would look for obvious dings.
The Stronghold chuck is quite robust. I easily have over 1,500 hours on mine. The chuck doesn't get babied, but I don't abuse it either. I have cranked the jaws pretty tight at times. So far the only signs that it is has over 50 hours is that the jaws themselves get dinged up with scratches and such.
If I was in your situation with 2 lathes, it might be time to break down and just get another stronghold chuck body.