Paramount spotting features:
Solid Nervex or Prugnat lugs (no cutouts) - post '70 bikes w/Nervex lugs have Prugnat BB shells. Campagnolo NR drive w/either NR or Weinmann 999 brakeset. Seat stays with plain angled caps. Nutted brake mounting. Braze-ons limited to chainstay RD cable stop, with exception to some w/rear brake cable stops on the top tube (others have clamps). If missing badge, there should be evidence of two holes, parallel on the horizontal axis, at the approximate center of the headtube.

Keep in mind, of course, the fact that someone might have NR'ed one of the lugged '80s models.

-Kurt