No, it does not.But it does mean that he (and any legal representation he had) thought he was more likely to be found guilty than not, does it not?
You clearly have an unreasonably high regard for the American justice system.
"prosecutors, judges, defense attorneys and academics cited "substantial evidence" that innocent people are coerced into guilty pleas because of the power prosecutors hold over them, including the prospect of decades-long mandatory minimum sentences"
Especially if you are black, poor and have a criminal record