Best I can remember, back in that time period, the hat rule was, if the wing commander approved it, the squadrons could wear hats of the squadron color with the squadron patch on the front of it. It could be legal for a long time, and then the wing commander got promoted, or reassigned. The squadron hats suddenly became illegal to wear. They were always, only for work uniform and never legal for any other uniform. Had a red hat with 776 TAS patch on the front of it. It was legal, then it was not, then it was. When the new wing commander took over, the custom hats were not legal until he actually approved them.