Early '73 models (built in late '72) could still have had 9" front brakes. Those went away after the first of the year. They used the same spindle as the 10" brakes, so, they were a pretty rare animal. Speaking of spindles, inspect yours very closely for damage. That photo you posted makes me cringe! If damaged, either get a complete set from someone here doing a BBP disc changeover, or, bite the bullet and swap to that setup yourself. It will require new wheels though, and either a second spare, or, a conversion in the rear too.