This quote was taken from a corvette site. It refers to a speedo in a '68...
"We wanted to freshen up our lense bezels so we removed them. On disassembly you will notice these small rubber pads between the gauge lense and the bezel. These are small anti-rattle pads. They keep the lense from rattling against the bezel. To freshen up the black painted area on the bezels and housing, start by cleaning them. Now use 600 grit or a fine scuff pad to scuff the black painted surfaces. Do not remove the black paint. By leaving it and just scuffing it, you can use it as a primer base. Now take 1/8" masking tape and tape the chrome outer lip of the bezel. Spray the black surfaces with a semi-gloss black. When it is done, remove the tape. Now you have gauge bezels and housings that look new."
Contact company to rebuilt these is; Zip Products, Inc. Phone# 1-800-962-9632. I am assuming they carry the paint. If not I am sure they can point you in the right direction.