Clear coat them once a month too. 4130 is an alloyed steel and will rust when oxygen touches it (oxidization), this is often why bars come standard powdercoated because it puts on a thick hard to break coat protecting them from rust. The clear coat of spray paint will wear off and scratch in places (after all, it is only spray paint, not industrial style powdercoating) so just tape up your grips and spray those bars monthly, don't lettem go longer than that or it'll be work later due to sanding off rust, etc.