I don't recall anyone asking for Jesus' forgiveness as he hung on that cross. Yet his words were "Father, forgive them for they know not what they do."
In John 1 we are told: “If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.”
The “if” in John’s statement leads me to believe that, on at least some level, the granting of forgiveness is conditional upon requesting forgiveness. I feel that if confession were not an important part of the process, John would not have included it in this statement.
I believe one of the theives did.