I have this suspect because after the third patch suddendly appeared silver and platinum coins, with this hotfix now there are electrum and coper coins (well coin piles).
There were platimum, copper, etc coins when Early Access release occurred - they have not been added, it's just that many never ever noticed them (in the Zhent Hideout, and a couple other places I can't remember).....
Only time will tell if they will have any real value other than the 'my pretties' weight they are come full release.