It's an oversized oval MOP being 50 x 80 mm... and though I have not seen any plaques with this exact monogram, there are lower denomination rounds which have been increased in value with the addition of a "0" which could be Argentina (the initials fit well... ¿Juan Hernández Gómez?). The seller said that I would never see another, and I believe him; and told him so at the time of purchase.