Muslim men are only allowed to wear one ring that is iron polished with silver. In many of these photos, that appears to be gold. (Yellow ring like gold or copper is expressly forbidden for men- Abu Dawud, Book 34, Number 4211, Bukhari, Volume 7, Book 72, Number 754, Bukhari, Volume 7, Book 72, Number 759)
Isn’t it possible that he later had that “iron polished with silver” ring, gold platted?
or....
It’s a ring FMD gave him.