Not really rare, but I don't think they had the production output they did later. You occasionally see them on eBay, and IIRC they go for a few hundred. I'd love to get hold of one for the neck - bound
ebony fretboard, and a profile pretty close to an "ultra".
They were the best bolt ons Ibanez had at the time (there were
neck thru prolines as well) - Japanese made, Edge trem, etc.