Regs say anyone can wear them
This is a “rule” that a few Sqns implemented (Shouldnt be). Regs should be followed by all however as a normal cadet you confronting your oc around it will result you probably being told to do one. Just pick your battles
However I would encourage you to point it out.
Approach your CO and say something along the lines of “Sir, I was checking my understanding of something in AP1358C and noticed that it says all can wear Stable Belts. Am I able to wear one?” You never know what the answer will be. If no, atleast you show one of the qualities that a NCO needs to have, an understanding of where to find drill and dress regulations.