If a bike has all of its original parts and you just clean and lube and replace consumables, it is original.
if you source parts to look like it’s original state with those parts, it’s not original since the parts were sourced elsewhere...it is “restored and era cognizant...”.
That said, you can keep groups together, update and upgrade, repaint, touch up, modernize...its what usually happened to bikes people owned over time anyhow. Replacing and upgrading.
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1987 Crest Cannondale, 1987 Basso Gap, 1992 Rossin Performance EL, 1990ish Van Tuyl, 1985 Trek 670, 1982 AD SLE, 2003 Pinarello Surprise, 1990ish MBK Atlantique, 1987 Peugeot Competition, 1987 Nishiki Tri-A, 1981 Faggin, 1996 Cannondale M500, 1984 Mercian, 1982 AD SuperLeicht, 1985 Massi (model unknown), 1988 Daccordi Griffe , 1989 Fauxsin MTB, 1981 Ciocc Mockba, 1992 Bianchi Giro, 1977 Colnago Super