That's right the old black 550's had Rosewood, and the other colors had Maple. Depending on the condition I'd say $300-$500 but its really whatever the market dictates. You might find that more people want Maple, or that black is too common of a color in RG's, Or you might find someone who'll pay $700 because black with Rosewood is more rare, I don't know.
Sorry dude, got my wires crossed there. Just checked out the Ibanez Register website, noticed the EX and LTD both had rosewood boards (with the LTD with the sharktooth inlays) and were available in other colours apart from black.