The reason for describing the complicated process that gave the original part the big galvanizing spangles was to imply it's an impossible dream to duplicate it. And also to say the process still exists but without lead as another poster said.

BTW this same discussion has been on this forum before concerning E-body license plate brackets originally made with the same big galvanizing spangles.

To be more helpful, there are a couple of other ways to deposit zinc on steel sheet. But neither is recommendable for restoring the part to its as-made appearance.

1. Electro-zinc plating - This will deposit a zinc coating of a few ten thousandths of an inch thick on steel sheet, about the same thickness as the original process. But there will be no spangles or crystals, because the zinc will not be melted.

2. Batch hot dip galvanizing - This is dipping the part in molten zinc like the original part was done, except without the very sophisticated control of variables that made the spangles. Besides, the pot chemistry is now different, the coating is around 10 times or more thicker, few dippers will accept thin steel sheet, too expensive, might not make spangles anyhow since there is no spangle control, etc.

Paint with special effects like wadded newspaper, etc., seems to be the best anyone can do with an impossible task.