This question need to be examined IAW the applicable Air Force (AF) Manual. Procurement of recognition items for Air Force special trophies, awards, decorations and memorialization programs is addressed in AFMAN 36-2806. Paragraph 2.9 says commanders and civilian directors may authorize the use of unit funds for reasonable costs, such as the purchase of trophies, plaques, certificates and other items intended primarily for presentation... Interpretation of the AFMAN is awards are given to those who made significant contributions to the AF or functional area. If the purpose of this display is to recognize all those who held a certain position, how is holding a position making a significant contribution?

Paragraph 3.1 says commanders use decorations to recognize meritorious or outstanding service as well as excellence above and beyond the actions of others. How does merely holding a position fall under this intention? Ultimately, this sounds like a question for your installation legal counsel.