Is that the signature of PO on the top tube and is it "Magni, O."? Would guess first name might be Ottavio or something like it, and that surname has some cache, but perhaps no relation to the marque. And BTW in case I missed this the headlugs are very similar to, but maybe not exactly the same Prugnat "62D" model lugs used by MANY builders, including highly favored by Ernesto for his Colnagos