Please see attached pictures. There are faint concentric circles in relief that surround the legends. What are these for? How where they made? The dies were probably punched, not hubbed. Could the circles have been imprinted on the dies to guide punch lettering? These are true circles. The legend letters are not all identical. The circles are not seen on other Rev coinage though Oaxaca may have been hubbed. Thank you in advance for any help.

