If you mean gold coins, hardly anyone is familiar with them. How do you make change?
If you mean silver, how do you prove the silver content? Fine? Sterling? Coin? Mexican? I have seen scam jewelers who do a nitric test in front of the customer and then tell them that the result indicates sterling, when it indicates nickle. The customer is bamboozled. How many Americans know the difference between a real silver US coin and recent ones with less to no silver?
I wonder if we will all posses gold testing kits and scales with dwt weights? If you go to a jeweler’s studio, he will have both and the stamps for all gold karats and silver content.
I look at my Walking Liberty $5 gold pieces, for example, as 10th of an oz, or, at today’s prices $100. Yet, they are stamped $5.
My scenario presupposes local currencies independent of the US government money of recent vintage. But, anything can be counterfeited, that is always a risk. So, maybe there is opportunity in selling test kits and scales and perhaps holding workshops to teach folks how to use them and how to interpret the tests.
Or maybe the entire gold/silver/platinum idea is a non-starter. Probably better to trade ammo.
It’s much easier to detect a fake gold coin than a fake $100 bill. You can simply weigh it.
When we are at the point of using PMs to buy food, then counterfeiting will be treated like cheating at cards and horst stealing in the old west. It will get you shot, so it will not be commonly done. A business which runs a fraud buying or selling fake coins is going to be lynched the same day. Through history, this has tended to keep people honest in very hard times.
Gold CANNOT be counterfeited, which is one of the top reasons it has always been a store of wealth. Nobody bothers to spend over 100K dollars to mint and gold plate fake Krugerrands, when simply putting the fake on a simple postage scale will reveal that it is base metal.