Thread: Need some serious help on figuring this guy out.

They are cast of aluminum. Sounds cheap these days, but back when they were made, Aluminum was a new alloy and quite expensive and desirable.

Aluminum was extremely expensive in the times of Napoleon (aluminum utensils were more valuable than silver and gold ones), but by the end of the 19th century there was better technology to produce it and it became pretty cheap. The airplane industry made it even cheaper because the governments started subsidizing the production.
By the time these scales were cast it was a run of the mill material - certainly more expensive than the plastics, but far cheaper than sterling silver.