I am restoring a 1956 Merc and had the same question so I did a little research, here is what I came up with...
1955 - Yellow or Cream and Tan
1956 - Gold block with Blue air cleaner and valve covers
The paint is available in spray cans from Classic Mercury ( classicmercury.com )
I couldn't stand the 56 colors so I painted mine Ford Red wit Argent Silver air cleaner and valve covers.
Pete