In this photo you can probably make out the flattening on the inside of the o-rings. Funny thing is that I thought I remembered them being flattened on the 'sidewalls' as it were - which is what I thought explained the lateral play in the swinging arm frame. I also remember them as being more flattened then they appear to be now. Possible that they reconstituted themselves when removed from the stress? Or I was just mistaken.
If the lateral play in the swinging arm frame - 1/8th inch back and forth at the pivot from side-to-side - wasn't due to the o-rings, then what else would explain it? Or is that normal? Hoping someone would chime in on this question.
As for changing the bushes, if they need it (play) and you are reasonably skilled mechanically, I'd say do it while you have the opportunity. I have no mechanical skills, but I know the ones on my Bonnie need replacing so I'm going for it. After all, I've already done it once. Nevertheless, I've been procrastinating for over a week because I can't decide which one of my sockets I should deface by grinding flat for the job (if it weren't for Covid lockdown I'd just go out and buy a cheap one).
But I wonder if anyone knows whether or not you could swap your old style end caps for newer ones with o-rings?
One last comment: I did look again at the o-rings I removed at 53,000 miles and they have no flattening at all. Neither are their inside radius pitted like the ones that just came out after 32,000 miles. What else could cause the pitting other than road grit? And if the road grit penetrated to there, why wouldn't it have made it inside the swing arm and the bushes?
So many questions. So little time and knowledge!