Yes there is.

The 5 wheels on my '69 Barracuda are X9 color as called out on the build sheet.

Plymouth X9 Black Velvet is the exterior gloss finish color used to paint bodies. See page 23-151 in the '69 Plymouth Factory service manual.

The factory paint on my wheels was still shiny a few years ago when these photos were taken, despite no wash or wax or any other maintenance for decades. Definitely gloss black.