You could be lucky and they might just be rust tendrils working their way under the paint. Not unusual to find on old steel bikes. In most cases the rust under them is mostly just on the surface of the steel.
Only way to find out is to remove the line of raised paint and check if there is a crack or not.

They don't look like cracks to me because a crack in metal normally is not curved.
Good luck, Ben

rust "tendril" AKA a "spiderweb of rust" under the paint on the outer blade, probably some wheel rub caused the chip on the inner blade, Id not be too alarmed by either.
Given the 27.2 seatpost you are correct to conclude probably SL tubing (rifled steerer would further confirm this) and a "Mockba 80" is as good a guess as any for the correct model.
Yes, the Pelizzoli signature decal was used for MANY years on MANY models long after Giovanni sold the name off to the Bonati or Billato (you tell us!) new owners.