I don't think ATACMS or GMLRS missiles have any terminal guidance apart from their aim point. The GMLRS missiles that carry german SMART munitions do, technically, since the SMART munition has it's own targeting system.
It wouldn't make much sense to me, as most ATACMS warheads are area based, not point target based, so they wouldn't expect to aim at a single target. Also these systems are relatively cheap compared to things that DO have such guidance
