Wayne - Nice bike! I had nearly the identical bike that I purchased directly from Alberto Masi in late 1982. Dave Martinez of the list has it now. It was Reynolds 531 tubing, although I don't know when they began using that. I heard that Masi had some sort of row with Columbus so started using Reynolds. Tange Prestige tubing did not become available until the early 80s, and I doubt any self-respecting Italian builder would ever have used it. I am sure there is no connection there. The lugs and crown and bb and seatstay caps are Italian investment cast. That is indeed a first-gen SR rear der. It should have a date stamp on it when you get to see it. I subsequently sold a dozen Masi Prestiges in the next couple years after I got mine. That was right about the time they brought out the 3V, so the Prestige was probably discontinued about 1984-5. I still see some of them occasionally. Mine had Masi pantograph stem and seat post, engraved shifters, Masi-engraved bars, Masi-labeled rims, and the inner web surface of the SR chainwheels were colored in yellow. Very cool. Also came with a yellow wool "Club Alberto Masi" jersey and flocked shorts, both of which went to Dave, plus Masi waterbottles and musettes. Came completely assembled from Masi, and then packed without disrupting any adjustments. Very Classy operation.
Regards
Bob Freeman