Ford affixed a brass tag to the radiator support of special order cars bound for company executives.  Ford also had brass keys for these executive vehicles.

The brass tag affixed to the car is an ID also placed at the  bottom of the invoice, example

• 300-L-162 first 3 digits of the organization the car was assigned to. The middle letter
  L – lease
  T – test had an M license plates
  E – executive
• Followed by a 3 digits serial # number assigned to a ford executive. 
• The brass tags were on lhe A-pillar or the rocker in front of scuff plate or on the rad support with screws or rivets.