Join us on Facebook: Search for 'ConcoursMustang' Private group!https://www.facebook.com/groups/concoursmustang/Indiana SAAC Fall Classic , French Lick, IN Oct 11-12http://www.insaac.org/SAAC National-Sanctioned Concours Event
Julian calendar, maybe?! The 4th number being the year. Just a guess at this point without knowing / seeing more examples.Danny