Old "Gold Bug 2?" NO. This is basically a gold-prospecting ONLY unit, designed to find even tiny flakes of gold. You would likely want either the new Gold Bug Pro, or G2 -- same machines, different cosmetics. There are a few versions of Gold Bug Pro out there, a couple of older-software-release prototype-type versions, and then the current version, but as a relic hunter you are probably OK with any of the versions. There are minor differences; I think some of the prototypes are VCO, some older ones non-VCO, if I'm not mistaken...but the units produced within the past year or so are all the same, if I'm not mistaken. Unless you are buying an older, used unit (or one from the national sporting good chain that sells what I think may be a slightly stripped-down model), then you'll be fine. Even one of the older models (or that sporting good chain model) would still be a good unit though, from what I understand. If you are buying a brand-new, new-stock unit, you have three choices -- a Fisher Gold Bug Pro (comes stock with 5" DD coil and thus geared toward gold prospectors), a Fisher Gold Bug "DP" (simply a Gold Bug Pro but comes stock with the 11" DD coil, with the 5" available for purchase as an accessory), or the Teknetics G2 (it is simply a Gold Bug "DP" -- the G2 also comes with the 11" DD coil as its stock coil -- but with slightly different cosmetics, and a different handle configuration as compared to the Gold Bug Pro).
I hope this helps you out; if you were wanting to know specific differences between the earlier versions of Gold Bug Pro, then there are some old threads here that you could do a search on, or -- if you ask more specific questions about the differences, I'm sure someone could chime in and help you out. I know some use this unit as a relic hunter, with 11" DD coil, with really good success...
Steve