I see what you mean about the shackle bolts being off center. Here's a better picture.
The off center spring bolt may well be an indication of wear of that bushing. But, when I last checked, the perch bolt was still tight (too tight to get out) of the upper hole that is not drilled in the middle of the perch. I guess I could check it by lifting the body up so the axle hangs and see if there's any movement of that upper bolt indicating wear. It's been a few years since I tried to replace that. I've never seen it move when I've lifted the body up and let the axle hang but maybe I wasn't looking closely enough. If it's truly worn loose in the hole it should be easy to change and I'll do that.