Generally your powder coater will show you samples of the various blacks. Much easier to see for yourself than attempting to describe over the computer.
Yes; to the best of my knowledge the originals were at maximum high gloss, certainly that's what appears in archives photos and NOS wheels that I've seen.
While I'm not a 100% restorer I currently have 3 deuces with 100% gloss black wheels and they look great. If I remember right when I toured the Seacrest collection back in the 70's all his black parts and wheels were high gloss black?