Gematria σοφια = παυλος = 781

[Ulan]

I just notice that the explanation may be even more banal than what you suggested:



The description of this piece says "inscribed either Saulos or Paulos".

[lsayre]

He may simply have been called both Paulos and Saul at birth, with Saul being his given Hebrew name, and Paulos being his given Roman name. There is after all the claim of Roman citizenship...