I've racked my brains to see how this could be considered offensive. It is probably a little in bad taste, at most. However, there is a long and distinguished history of students and young types with outlandish hairstyles wearing military surplus uniforms....in my young days (harrumph) it was girls with dyed hair, German Army shirts and boots.
What should be of grave concern is the limits precedent this could set for selling on old uniforms after retirement!
I kept my No 1s and No 5s, wouldn't want to sell them on personally.