I was interested to read this, as my Olagnero has a similar sticker which notes that Dossena Carlo used a mica pearl varnish.
I wouldn't get the Nag resprayed if it were mine; as suggested above a sympathetic touch-up job will make the world of difference.
Being under the top tube it won't be immediately obvious and a bike of this quality is worth preserving in its original paint.
I'll take "patina" over "pristine" any day: it's only original once!
I also have an Olagnero with a Carlo Dossena pearl job, he did a lost of gorgeous lacquer work around Milan...hope you find someone who can renovate decor paintwork!
Colnago Super, C record Delta 7v,
Olagnero Signature Model, DA 7401
Battaglin EL101 tubing 8v
Wilier Campagnolo 8v Record
Daccordi Furioso, Campag Veloce 9v