In the case of the MBCA Silver Star Preservation Award, my understanding as a take-away from our training was, that an officer in the local chapter of the club was to verify, in person, what an owner represented about his car, in terms of originality, on several forms that he filled out. The officer is to do so only during a MBCA-sanctioned event (National or local level).
The chapter representative then verifies what the owner states. That's it. Then he signs it, and sends it off to MBCA HQ. This is a much less formal and competitive process, as compared to a judged national concours show, such as Amelia or Pebble. No trophies or public announcements are involved. (Although a nice grill badge is available for purchase if an award is made).
There are criteria provided by the MBCA to use when weighing the originality of the car. It's a points system, starting at 100 points, with points deducted for various replaced or non-original parts or finishes. It's a very objective process actually. Either the item or finish is original, or it isn't. If it has been replaced, either it was replaced with an OEM part, or it wasn't.
With this particular car, there were hardly any points deductions taken at all, due to the car's very original condition, as presented.
This being an award created by the Mercedes-Benz Club of America, I don't believe that you have an equivalent award such as this on your side of the Pond, or am I mistaken?