Great find, Norman! It is interesting that in the background you can see smaller pastries on the table, but you only ever see pies and that huge cake come into play. Oh yes, and Jack Lemmon throwing some kind of cream at some dude with a spoon at the end.
The color picture has been around for awhile. I havent seen the B&W one before. I bet its the makeup area. The Life magazine article in 1964 said that at the end of each day, the makeup artists took color photos of each actor, then the next morning carefully reapplied the appropriate pies. Those "cupcakes" might be the extra pie filling. Note the briefcase in the lower left, the man in the upper right who was not seen in the film and is clean.