A little history on this style lock. Two different vault door locks were used on the model 50A Pay Station. The first was the model 14E flat key style. They then used the style the 11A lock or Corbin lock shown in these pictures. It was a higher security lock since it used the grooved keyway. Both style locks are shown in the Gray book with the 50A. The flat door with this style lock was used on the early 50Gs beginning in 1920. The key is not an original but uses one of the earliest ILCO blanks for this style lock and works perfectly.....the lock has not been taken apart.
I believe Corbin made these locks for Gray. I have only seen two locks with original keys and they were both on 50As.

You receive only 1 key.