Mayweather Sr learned the shoulder roll from someone born around 1900

No idea about William's but George Benton was obviously taught the shoulder roll and he was boxing decades befor Sr.

 

Should roll was used by fighters before SR

 

Fight Hype made a mistake. It was Del Williams, who taught Mayweather. Del Williams was an old timer, who was around the same age as Eddie Futch and they learned to box together.

Dale Williams on the other hand was a pretty well known assistant trainer back in 70’s and 80’s and worked with the Spinks brothers, but mostly Leon and worked the corner of a ton of other fighters under Del Williams. In the fight between Larry Holmes and Leon Spinks you can see Dale Williams throwing in the towel after being told to by Del Williams. Dale Williams would’ve only been in his 40’s during the mid to late 70’s.


“Williams, seeing Spinks was no longer fighting back, began waving the towel. ''Should I throw it in?'' he asked Del Williams, the 67-year-old chief trainer for Spinks and no relation to Dale. ''Go ahead, throw it,'' said Del Williams.

Del Williams grew up in this city with 69-year-old Eddie Futch, Holmes's new trainer. Williams and Futch learned how to box together at the old Brewster Recreation Center, where one of their teammates was Joe Louis, and Williams and Futch later trained fighters together. They are old friends.

And Futch was the trainer who refused to allow Joe Frazier to go out for the 15th round against Muhammad Ali in 1975. Holmes thought the merciful act of the two Williamses was in sharp contrast to the job done by Steele. ''What is boxing coming to?'' said Holmes. ''The man was out on his feet and the man let him take punches. It don't make any sense.'' Holmes had said that Spinks ''would bring out the best in me,'' and though this was his 38th victory, and 28th knockout, he has seldom looked better.”
https://www.nytimes.com/1981/06/13/...n-3d-round-and-retains-heavyweight-title.html

 

Archie Moore was also taught the cross arm guard by Hiawatha Grey, who was a late 1800s boxer.