Yes.

The way I see this, is that Joe Pistone truly believes that unless these men are proven guilty beyond a shadow of a doubt, that their badges and honor should not be questioned.

You have to remember that he was one of 45 FBI agents who showed their brotherhood and support toward Devecchio when he was on trial.

Is there a possibility that Pistone knew Devecchio was guilty as sin and yet still tried to unravel his friend from being convicted with the enemy (Scarpa)? It's possible. It's possible he felt Devecchio went too far and got caught up in the gangster thing accidentally, unintentionally. It is even possible that he felt that his friend sinned but did not commit an unforgivable sin and that lying to society on his friend's behalf to justify his misdeeds and clear his name was his duty as a brother law enforcement officer. My own opinions on the matter are evolving. I would be lying if I told you I almost didn't buy a copy of "Deal with the Devil" a short while ago. That would not be true because I almost did.