I would like some information on the rear rotor shields for 68 corvette. I know they should be silver. I don't recall if they were zinc or cad plated. I have noticed that there were differences in the size of the part numbers stamped into the baking plates. Earlier one's had small letters and later one's had large characters. Does any one no the cut off dates for the color chages from silver to gold and the date changes for the character sizes. Also, I am looking for a nice set of silver backing plates with small characters (originals) that are in good or better condition (a little rust in the bolt areas is ok, oxidation ok also). Thanks, Terry