If he had loss(es) I guess it would depend on who beat him and how.
Rather than claim he is undefeated, he'd claim he was robbed ala Bhop style & keep on fighting.

I think a loss would've required a rematch, to which he would've won-as did when his questionable victories were called into question

One thing for sure is that virtually all great fighters at some point got the benefit of the doubt.

Marciano was in a fight where his nose was near torn off. Any other fighter & it would've been stopped.

JCC got a gift draw vs Pernell.
Ali got gift wins like a kid gets gifts on Xmas.
Ray Leonard got a gift draw vs Hearns II..and stated he loss that fight hands down.
DLH got a gift win vs Quartey

Most big named fighters will always get the benefit of the doubt.
For the record, as close as the Castillo I fight was, I had Floyd winning 6-5-1, Floyd is undefeated.