Thanks for taking the time, showing all the very nice good rings and the fakes Gaspare.
Here you buy only the dealer's story (and a bit material). I's the first fake ground dug of this kind I ever have seen.
Imo the "heavily corroded holes" (the one above and two down ) have more or less the same cut out shape and size, treated with acid . Originaly corroded it would be more irrigular in this grade of corrosion, but then it would disattrrack the ring. This last one is really an interesting fake.