The numismatic value is only what the market will bear, and would take a while to achieve. People would be asking all sorts of questions, trying to ascertain the coins’ authenticity, since there are many fake coins, though made of real gold and silver................
No, melting down 15th century sovereigns would be retarded. Here’s why.
There would be no problem whatsoever selling them as-is, and once they are turned into an unregnizeable blob of metal, that in turn would need to be assayed. When dealers purchase bullion it is bought at a very steep discount to gold price because of that.
Overall a good problem to have though. The stash represents somebodies life savings btw. Always a wonder what happened, why didn’t they return to get it. It’s cute their government has this “well they were trying to hide it, so it’s obviously ours”. What a bunch of wankers.