My thoughts - I think the one " you came across" is a counterfeit. Apart from the coin having a good dip, looking at the horse's bottom jaw/lip : the jaw/lip seems to be " hanging " too close to the horse's chest.
The rider's left arm is " unusual " from what is the norm, the horse's leg knuckles are " unusual ".
It also appears as though the horse's head is joined onto it's chest instead of having a clear visible gap.
If I can get the time, I should have a look at the MCFs I acquired in the 1960's. I believe they are " kosher ".
All/any input from as many contributers to ACC is invaluable to all of us.