there are a few points however
if you produce a die from an official coin , you ll get a die without errors.
so the many dies with errors must have been produced ad hoc.
secondly these dies who produced these
fouree were very very well made, i doubt you would have been able to produce one in an economically viable way.
i mean that to be profitable the forger has to contain
his costs , there s no point in producing a
fake 20$ bill if you spend so much time and effort that the end product costs you 22$.
so you are better off casting with a clay mould rather than going to the trouble of producing a die.
producing a
fake coin is not a simple process , for example some of the recent
chinese replica can be spotted miles away , same story for a few of the
fake romans in the
fake reports.
then you have the matter of producing a thin silver foil , which is not technologically simple
in your page you mention the wax copy , then a clay mould and then a die , but i doubt that using a process like this you get such
sharp details.
i have seen a few coins made from casting and the details simply do not come out , so i doubt that casting a die using a clay mould would result in anything useful.
my main objections however is simply on economic grounds, if you are a forger you go for something cheaper and less labourious.
bear in mind that during the middle ages to modern time forgers never reached a level of sophistication shown by these
fouree unless they were produced in organized mints.