I would consider cleaning, filling pits and at least prime the inner transom aluminum, along with the brackets and channel.
Get a couple nylon wire brushes for a drill. There color coded for grit, but most places just have a mild grit one. They won’t contaminate the aluminum with steel, and don’t remove as much aluminum. I have one with no grit, but it’s just to scuff or clean.
I used Marine Tex and a couple $5 tubes of JB Marine epoxy, which looked a lot like the Marine Tex. A bondo spreader and a skim over the pitting is all you need.
I guess maybe you already planned on doing all that and Im wasting my time here, lol. If you want that wood to last longer trouble free you could epoxy the wood. A quart should do a transom. I used System 3 S1 penetrating epoxy sealer. I did my deck with it also, and 2 gallons did both and some to spare yet. It’s 1:1 so you get 2 containers of part A & B, same size. With the price of Spar here, it worked out to $20 more a quart I think.
I paid $250 Canadian for 2 gallons, that’s $65ish a quart, probably $40 USD. The stuff reeks though, so take that into account.
Glad you got that bugger out. Mine wasn’t too bad and I took it out with the boat turtled so gravity helped. I remember scratching my head looking for bolts, or screws that I missed.