Motox, on most HD tanks there's a tag on the bottom with the color NAME (not a number code) and date.you may have to pull the tank on your bike to see it. Or you can go the easy way and just look the a HD brochure for colors on your model/year. I've mixed a bunch of HD colors on the mixing system where i work. Any paint jobber that's in the 21st century should be able to help you out. Just make sure they don't sell you lacquer.
Osh