Events of Red Dead Redemption 2
After the mission "Motherhood" in the Epilogue, the player is able to visit his barber shop next to the Blackwater photography studio where Wilton can cut and style the John's hair and beard.
He offers the same services to the protagonist of Red Dead Online.
Events of Red Dead Redemption
Although Wilton himself is not encountered in Red Dead Redemption, his shop is still present under his name in Blackwater.