Stan, GB or Whomever...What is the assayer here

[Trez]

Stan or GB or other...

Need your thoughts on this one...it is a Mexico 1 real, date early 1600.
But the assayer, is it an assayer over another assayer F over E

[divewrecks]

Looks like an E was mistakenly used and then overstruck with an F. The reason I think that is that there is a 1 reale assayer F coin in Menzell's book (left hand of page 86, second up from bottom) where it says an E was substituted for an F (considered rare). The denomination is to the right on this coin, but it shows the foul-up had occurred at least once. Perhaps through similar circumstances it happened again and this one was caught and "repaired". If so it could be very rare and perhaps the only one known. I will look in some auction catalogs later. Anything worth looking into on the other side?

Stan