This is a later Vega made original 5 string Tubaphone banjo.
It no longer has the fancy #3 inlay but the huge 1113/16" pot
makes it sound even more distinctive Tubaphone sound.
A shorter neck and an extended fingerboard give it a unique
outlook. Probably a neck blank pre-cut for a tenor banjo was
used and finished as a 5 string banjo.
It also has an elaborate heel carving and make it a #3 .