cassharper;3072748; said:1966: Defeated by Ed Steen
1967: Defeated by Marcos Solar
1968: Defeated by Louis Delgado
If you meant that he was not defeated while he held the title, then that is correct; which he earned not long after his defeat by Delgado. I'm not trying to take away from his talent by any means. Aside from being a nutjob post martial arts career (only in my humble opinion) he was one of the most amazing fighters I have ever seen.
You are right, I'm still not sure why his site states that he retired undefeated, I don't know if that means he was undefeated as a pro, or as a middle weight. According to wikipedia he actually lost ten fights though. I believe they may have all been to the same three fighters though just on several occasions.