If you are referring to face value, it would be worthless. The Mexico peso has been devalued more than once, in effect, making money issued prior to the devaluation to lose its value. I was just in Mexico a month ago, and I tried to spend a few coins from the 1980s and the banks told me it was no good/worthless. The last devaluation of the peso was in Dec. 1994. If you want to know what it would have been worth if it were still valid, the best exchange rate when I was there was 13.98 pesos to a dollar, but it would be bogus to apply that rate to your coin because of the other devaluations. If you are asking about value to a collector, someone else will have to answer that question.
