Yes, the axle housing is the same for all the variants of the 14-bolt as far as I know. It's all in the hubs that make the difference. A complete 14-bolt axle can usually be obtained from the local pick-a-part junkyard for right around $100 all day. The only concerns I'd have with that is the spring and shock perch locations. On my Suburban, which is the 80s bodystyle, the spring perches are narrower than the new pickups, so I had to have mine moved. But, with yours being the newer bodystyle, it may have the same spring perch locations. A tape measure will tell you for sure.
Getting a whole axle from the junkyard is nice in that you can take your time and rebuild the whole thing before installing it into the truck. On the other hand, a hub and axleshaft swap can probably be accomplished in under an hour with 1 person and the right tools. The brakes are a question here depending on whether your drums slide over the hubs or get pinned to the back of the hubs with the lug studs. However, with the hubs, axleshafts, and brake backing plates off the same vehicle, it shouldn't be an issue. Keep in mind also that your wheel mounting surface to wheel mounting surface will change when moving to duallies, but that's offset by dual tires.
If you have any other questions, just ask. I've rebuilt a single wheel 14-bolt and a dual-wheel 14-bolt axle in the past year.