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
At the plant likely for lining up the sub-structure in a jig to produce a subassemblyNothing attaches there on a completed Mustang
More commonly called "tooling fixture alignment holes". Jim