I have seen those types of rings or whatever they are called before on Hollowbody Gibson's and was always perplexed by them and why they are there in the first place . If anyone can shed some light on this I would be most interested ?
I always understood that "goof rings" were used to cover some finish chipping around the pickup routs. Have seen them on tailpiece stud holes too though. Seem to mostly appear on early 70s deluxes with Mini Humbuckers but I have seen them on some of the late 60s reissues with P90s as well.
Horrid things held on with some little nails!!!
Regards
Rob