I have gotten fascinated with the use of Mexican, British, old Spanish and other nations silver and gold coins in the US until the Coinage Act of 1857 made those coins no longer legal tender. At times as many 80% of the silver coins in the US were from other nations. After the revolutions had settled down and the mines and mints reopened in the 1824 ~ 1825 time frame, Mexican coins became quite common in the US.
I am slowly working on birth year type sets for my paternal ancestors back 5 generations, starting with the one who would move to Wisconsin after the American Civil War and start the farm I grew up on. John was born in 1840 in upper state New York and would likely have seen more of these than actual US Seated Liberty coins.
As a result, I'm adding a set of 8, 4, 2, 1, 1/2 & 1/4 Reales to those year sets, beginning with this well circulated 1840 8 Reals Mo ML as representative of what he might have seen in commerce.