Ok...........A is the older one. It has come to my attention that C might have a separate ganga, so maybe pushed back to 1910s-1920s.

On copper baka-baka clamps: I think it was more of expense and status rather than age. Often these baka-baka (the Mindanao term) were made of copper, silver, swassa/suassa (a gold/copper alloy), or steel.

Thank you.

Does swassa tarnish?

Yes, but once cleaned it keeps shining for a very long time, it needs very long until it tarished again.

What Detlef said.......

The copper in the swassa makes it tarnish black over time. However, the gold in it delays it somewhat.

I think it really depends on how much gold is in your suasa mix. There is no real percentage that is written in stone.