My thoughts are that any primer is better than no primer. Primer provides a surface for more effective bonding with the paint. If the aluminum is coated then it is protected from corrosion. So that’s a good job and leave it at that.
William

I am a proponent of alodine and Zinc Chromate (or Zinc Phosphate) primer. Epoxy primers work on relatively firm/stiff substrates (limited flexure), but GA planes flex a LOT, so I like getting that conversion coating (Alodine) and sacrificial Zinc layer setup before puting urethane over the top (or, in the case of interior parts, just finishing up with the primer). For the interior, a coating of Corban 35 over the primer does wonders!