i have more then a few of these but dont have anything fancy in the way of serial Numbers, i like these especially sense there so inexpensive to collect but have noticed a substantial increase on the 500 Peso especially A/U examples can go in The $50 range, if you can even find them, i have a gem one that i bought about 5 years ago for $20, and the 1,000 peso is getting there as well but the design and the note are smaller so less of a premium.