If he was that "ripped" but had 18" arms, he would have done just fine. Did he ever compete against any of those people you mentioned?
He competed against the top guys in the shows he entered.
Very few bodybuilders had actual 18" arms in the 1950s when Gironda competed until steroids came along.
http://musclememory.com/show.php?s=vince+gironda&g=M1949 Pro Mr California - 4th
1950 Mr USA, Did not place
1951 Pro Mr America, 2nd
1956 Mr USA, Did not place
1957 Mr USA, 3rd
1962 Mr. Universe - Pro - NABBA, Short, 2nd