Chrome experts please......
Without knowing what specific piece you are talking about, remember that we are dealing with three types of parts. Pot metal parts like grill parts, tailites, 'A' post, door handles are chrome plated and can be identified by their heavier weight and their tendency to "erupt" or pit. Bumpers are chrome plated steel. Some trim pieces are stainless and are polished, not plated. Then there are the anodized aluminum pieces which are typically grill and trunk pieces. The factory polishes them and clear anodizes them to prevent corrosion. Typically in restoration the anodizing will be chemically removed or polished through, then the polished aluminum can be re-anodized or left bare (but will need maintenance). Sounds like your part is aluminum as they tend to "fog" with age.