For a fit-inducing thing as far as intonation, there are several versions of them. That $90 one is pretty early. Your $76 one is a bit later. You can see the difference in the "hooks." The earlier one has narrower hooks, while the later one is more rounded, bulbous. It also looks shiner - I suspect they plated them. There are some that are hollowed out if you flip them over. I guess those are among the last variants. Those are for sure plated, and I think made of nickeled or chromed brass. I believe those early nickel heavy muthas were used from 1953 up until 1963/4 when the one with the more substantial and post snugging hook shows up. Then the hollowed out thing shows up until it is phased out in 67 (someone paid $172 for one the other day!!!!!!). I wouldn't be surprised if they started doing that one on Kalamazoos, but I had them on a couple of regular Gibsons stock.
So, one of these days. I never really look for them, but the alert was too tempting.
