Congratulations to the very astute Ray Dobbins for being the first person to point out the anomaly on my 1978 De Rosa photos posted to Wool Jersey yesterday:
Note the use of a nutted front centerbolt and a recessed rear. Fork is definitely original to the bike, and suspect it was simply a shop error, grabbing a prebuilt nutted brake fork from the rack and fitting to a recessed rear frame. Greg Softley's ex-1975 De Rosa has a similar mismatch (think he purchased this from Ken Denny), although opposite of mine (recessed front & nutted rear):
Would be interested if anyone else owns a bike from this period with similar mismatched brake mounts.
Kevin Kruger - Grantville, PA USA