If I was in the market for another, I would have bought it. It's possible it has sat boxed for years, hence the condition.
Do I think older Customs are under valued? Well, I have a conflict of interest because I own one! It is important to note when you look at my pistures that I wanted a BRAND NEW 1973 SG Custom, the very same as the one I used to dribble over when I saw it in the shop window when I was 14 years old. They were so expensive at the equivalent of about $700, it might as well have been a million, because there was no way I could ever have afforded to buy one. So I swore I'd get one some day, and some 36 years later, I did. I had it completely refurbished to make it like the one I always wanted. If that's heresy, I don't care, and if that's selfish in destroying the so-called antique value, I don't care either. As for the 3 pickup arrangement, for sure, it's a pain sometimes, but it's just like driving a different car: you get used to it. Do I use it? No. It hangs on my music room wall so I can admire it, just like I used to all those years ago with my nose pressed against the shop window.