Components have improved more than frames, and frames generally outlast components, so putting newer parts on an older frame is a common practice. This is one reason I bought Capo #2 (actually, the third I have owned), which has almost all original components, whereas Capo #1 has been updated with a 1970s driveline.
If you don't like reaching down to shift downtube shifters, barcons will look more correct than brifters, with the added benefit of much greater mix-and-match flexibility.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069