Re: 1991 RG550 Neck Set Up
When you say "first fret," are you saying that the string is buzzing on open, and seems to be hitting the first fret because when you fret at the first fret it clears up? Or are you saying that when you fret the first fret, it buzzes?
If the firmer, then you absolutely want to shim the nut - Rich sells dedicated brass shims, but a cutout from a soda can or folded aluminum foil works in a pinch too. If the latter, to me that sounds like a slightly high second fret, and while increasing neck relief might help a tiny bit, more likely than not you're going to want some attention from a tech to lower that fret slightly.