1921 Un Peso overdate--ever heard of one?

Kaelasdad

I have a 1921 Un peso, and while examining the coin i see the remains of a number under the 9--I have looked a bit and seen no mention of an overdate for this issue--is there one that might be 1921/1821? It is either a 3,6,8,or 0 as the underlying metal shows the bottom curve. pictures to come, the email from my phone to my computer takes a little while.