The factory paint was VERY cheap gloss black. It didn't have the shine we are used to seeing from gloss today. I'd go with semi-gloss.
Lots of other suspension components were bare metal. UCAs and LCAs are bare metal. LCAs were dipped in cosmoline. Other bare metal parts came straight from the foundry and have a dark gray color to them.
I really like Rustoleum Professional semi-gloss black 239107. Comes in a 15 oz. spray can and sold at Lowes stores. Takes a while to cure but very durable. Also available in quarts if you want to use a spray gun, and you can also catalyze it with Valspar 4725 enamel hardener (Amazon) if you have the proper respirator and desire a faster cure.