You could go to this Forum's library, look up topic "Mustang Hardware Spreadsheet - (pick a year)", call up the spreadsheet by part number and look up hardware part number 370168-S10. You will find dimensions I measured from a couple of Mustangs, and see the source references listed on the right hand side.
I have two versions of "Ford Car Parts" (aka MPC), the 68 and 75 editions, and neither have a part number listed for the staple, in the illustration section or in the text, in conjunction with Ford base number 16A238, the seal.
Jim