THEORY: RDR2 states will have license plates in GTA 6, and we've already seen some of them.
New Hanover has an Oklahoma-esque license plate as the state represents Arkansas, Oklahoma, and Nebraska New Austin has an Arizona plate because it represents New Mexico, Arizona, and Texas Lemoyne has a Louisiana plate because it represents Louisiana Ambarino has a Colorado-like plate because its name is a parody of Colorado (Ambarino is Spanish for "amber coloured" while Colorado is Spanish for "coloured red")