When I was visiting Vienna back in '98, I wandered into a bike shop that was an RIH dealer. They had one that appeared to be a carbon monococque, a few that were lugged steel, and one that was a Vitus 979 with RIH decals - frames from at least three different factories. Based on that, I'm not sure there's an easy way to determine the "legitimacy" of an RIH (at least not in later years).
IP Merkin Providence, RI
PS - The shop's coolest RIH was a mini frame (like the one that Alberto Masi holds in a promo photo I've seen) for the sole purpose of displaying the new 9-speed Record Group in their shop window. I suppose I should try to find my trip photos and post 'em somewhere. If I may further digress, the shop owner claimed that it was the oldest bicycle shop in Vienna, and the oak parts cabinets lent a little bit of credibility to his claim. I ended up buying a half dozen RIH caps (with Campagnolo printed on the side) for the crew at my favorite bike shop (Outspokin') in Columbia, SC, where I was living at the time.