Later in the war, the US changed the packaging on their K rations in order to improve morale, with snappy designs on the same food. These boxes contain no food, but are perfect for your display.
The box says:
Ration Type K
Open inn bag carefully. It may be used as a waterproof container for matches, cigarettes and other items. For security, hide the empty can and wrapper so that they cannot be seen.
Meat and Eggs: eat cold, or after heating by boiling can in water. Assorted Biscuits – Coff: add to one-third canteen cup of hot or cold water. Fruit Bar: eat cold or make into jam by stewing 3 – 5 minutes in about 4 spoonfuls of water. Sugar – Chewing Gum – Cigarettes