Rear axle swap

Alright - I have a 2004 Sierra 3500 dually. One of the bearings seized at only 26k...making one side of the axle useless because it ground off the end of the tube. I've been doing days of research and coming up with very little from bone yards. I did find one axle, but it's got drum brakes. My question is - can I just switch the brakes by changing the whole thing over from the backing plate? There's 5 RPO codes on this, and 4 of the 5 match for my truck from the donor truck. Obvious is the brake option. I'm pulling the rear end today, and hope someone can shed some light on the subject for me. I'm betting on the brake changeover - because if it isn't right then I'm going to have to drive 8 hours away to get this thing!!

Ok apparently I've overlooked something here, and that is the mounting for the backing plate. From 2000 and lower the backing plate mounts are completely different (and much smaller to boot). So going with anything lower than a 2001 is completely out of sight.

Now to a different question...looking for an axle that is the "wide track" option - can you replace a non-widetrack axle with a wide track axle? It's a platform truck, you there's a lot of room to spare.

Hopefully someone will learn from my days of experience. The difference between all of these axles goes like this:

Chassis Cab options for wide track and non-wide track will not interchange.
Wide track backing plate to backing plate is 60", and perch to perch is 49 1/2"
Non-wide track is 52" B2B, and 40 1/2" P2P.

Difference between manual trans and auto trans is yokes. The housings are different at the yoke, and you can't switch yokes.

The years affected are 2001-2007.

Oh yea, 3.1qts of 75-90 SYNTHETIC.