I “googled” ’54 Mercury Sun Valley and came up with the following information regarding color for these cars.  They were only available in 2 lower body colors according to the article.  Those were yellow and mint green.  Both came with a dark green top.  You can find the original body color of a ’54 by looking at the first two numbers on the data plate (located on the drivers door jamb) under “body specif”.  If your car was an original white car that number would be 22.  The black one you reference would have an 01.  Post that two digit number and I will tell what the original color of your Sun Valley is.