This isn't perfect, BUT, you can get new/replacement black plates to put on your brown unit (or if you just need to spruce up your existing radio) using this company. There will still be a lot of brown on the radio, but it's a subtle improvement.
This is a pic of a brown unit with the new black faceplates... again, very subtle, but it's still nice to have new clean markings on your radio if nothing else..
engravers.net
TKM MX300 Faceplate Inserts Material - Made from .020” black with white text. All are backed with double faced tape for easy peel and stick installation. Price $31.25