Hello Paul,
I'm pretty much with Marius on this one:
The usual copper-based alloys for coins are quite soft - it doesn't need any sophisticated heat treatment for even very mild steel to become tougher than coins! (BTW, keris are traditionally not tempered which would need controlled re-heating the hardened blade to a fairly low, bluish temp specific for any given iron alloy - not really needed nor practical for laminated blades.)
You show two keris with very pronounced ada-ada: In my experience any of the traditional blade and tip geometries do perfectly well for coins... (Since armour in the Malay/Indo world tended to be pretty basic, I doubt that nicking coins tells us much about fighting function in the old times.
)
Any keris blade that does not pass this coin test needs to be retired from "active service" as a sidearm and it usually will be a "ghost" blade that lost much of its body from erosion (rust and washings). Of course, such a worn blade may still be a valuable pusaka and/or retain any intrinsic powers (isi, etc.).
Regards,
Kai