Those concreted coins that used to sell on eBay etc were supposedly found by metal detectorists in the former southern Warsaw Pact countries, but largely were modern fakes. There is an ancient coin collecting specialty that concentrates on ancient counterfeits though.
My son will buy a fake (at fake price) if he already has an original of it.
Seems like a lot of work for 20-30 bucks a pound.
But then this was 25 years ago that I was doing it, and $20-$30 was worth a lot more back then, so maybe it was worth the effort.
I know a lot of the NICE eBay coins are fakes. Look like they just came off the anvil on a polished flan, not buried for centuries.