Hi !
I already read them in a another topic but it's not enoughto be sure at 100%. I think that you can have a idea but not more, if the coin touch the table in a angle you can have a sound and if I touch them in another angle it can be different sound.... I don't know if you enderstand what I mean.
This method can be good for scrap coin's, same is mint coin of this date have not a big value I don't think that it's the better idea for collection coin unless someone collect them circulated.
THanks again for your help !