Need ID For Mexico Revenue Stamp

Can anyone help with an ID of this Mexico revenue stamp? It IS a revenue, right?

It was part of a $5 stamp show lot and I really like some of the old Mexican revenues, so was glad it was hiding in there.

Yes, Mexican revenue. You won't be surprised to find out that this is from the 1892-1893 series. Yours is the low value of five values in both Forbin and Mendoza listings. It also has the lowest CV among the five in both. Forbin CF103, Mendoza CF91

There would have been a talon on the bottom as issued.

Forbin notes that these are not often collected because they were not affixed to documents. At least, I think that's what they're saying.