Maddenma,Are you talking about key guards or a pants guard? They all came with key guards covering the key cups on the lower keys (Eb1/2 to Bb1), but only a few have an actual pants guard covering the rest of the mechanism. The pants guard is the bit that protects the rods from the spatula down to the bell keys and then connects to the key guards on the bell. It's curious omission that I can only attribute to cost avoidance during manufacture.
You are correct. I do actually mean the pants guards, not key guards! I will send you my email soon.