I remember reading that somewhere, too... Mine's a '99 one-peice, as well, and while i've never played the UV (i know, i'm lame), it sounds like mine'd be from the UV as well- it's noticeably thicker than the Wizard on my RG-520 i sold for it, but i just assumed it was because of the extra string.
Anyway, there was a thread about this not too long ago,i believe... I guess they did reuse some UV necks. Kinda cool, ain't it?
-Drew