You will need to strip the coating off (would not suggest blasting since that will change the surface texture unless you follow that up with a ceramic tumble)
We finish them as bare new steel (I like gun bluing brightened with steel wool but plenty of other paths to the same look) with weld blue at the stud end (where the one plate attaches to the two studs) and a heat treated look to the stud.
IMHO this best reproduces, for me, the two tone look of originals