Mexico 1869 Ca 8 Reales- no picture variety question

coinkat

So I recently bought an 1869 CA 8R and noticed the the second M of the MM assayer features an inverted M under the second M. It is in Dunigan’s Resplandors Book as a variety. He writes that it is very scarce but does not elaborate as to surviving pop by grade for the variety… just the date in general.

So the questions are…How scarce is this coin at the EF40 level? And would it be submission worthy at EF40?

Thanks in advance for any thoughts/commentary