These were made during the Leo Fender era - probably from 1976 to 1981 or so. On these old Leo-era models the roman numerals indicated the neck radius - I believe the "I" was a 12" radius and the "II" was a 7.5" radius. Old Leo used the same nomenclature on the very first G&L guitars as well (since they were made in the same factory by the same people).