YD3.1726 is now believed to be the correct Valencia Motor Show car (previously reported to be YD3.1725).

From MGA Twn Cam Production Data:
Chassis Number:       YD3 1726
Production started:   23 March 1959
Production completed: 24 March 1959
Car despatched:       03 April 1959
Body colour:          Old English White
Trim colour:          Red
Hood colour:          Black
Accessories:          Heater
                      ShTyres 
                      Sliding Side Screen
                      Black Tonneau Cover
                      Windscreen Washers
Engine No:            1333
Owner/location:       Known to be in United States (Mar-2009)

Notice the "ShTyres" option. This would be special Dunlop Show Tyres with the Dunlop Decal in white.