Not that it matters, but on this side of the pond non matching serial numbers would be a big issue.
Gun register on a national database is mandatory, so numbers must match.
When going for a extra set, they would be registered alongside the receiver, or if buying a new set from the factory the original serial number would be stamped.

Regardless, it doesn't affect your gun in any way, but I can see why a buyer would hesitate on that issue. I would.
Perazzi's, like all guns, are supposed to have matching numbers.

Litt's composed guns wouldn't find a buyer here, unless they were a bargain, and would be hard to register in any EU country.