According to this eBay listing for a metal token:

http://www.ebay.com/itm/Good-For-Token-HAVANA-CLUB-LEO-GUON-PROP-Mandan-North-Dakota-2-75-S-H-/351672221249

And at the very bottom of this historical article, Leo and Mike Guon are shown as the owners of The Cave, a bar in Mandan:

http://www.mandanhistory.org/areahistory/prohibitioninmandan.html

Apparently Mike Guon's past criminal record was not a bar to his obtaining a license to run . . . a new bar!