Watch List notes:

Mexico City, Mexico, 4 reales, Charles-Joanna, "Late Series," assayer O/L to left, mintmark oM to right (O/L-oM).Nesmith-106 type; Cal-139, S-M10; KM-18.13.69 grams.Very rare overassayer with none known to Nesmith in this denomination and first we have seen, a choice VF example with nice toning around details, some loss of metal on one edge, overall very well struck unlike most coins from assayer O (more typical of L).
($400-600)