Good point with new wheels, the new gears or new wheels might offset each other with the price. But then ill have heavy duty axles, plus I think theres something broke in one of my front locks right now. I got time to decide.
If you're planning a gear change, I'd certainly agree with GD on that upgrade. And then you're getting used axles that you can be fairly certain were set up right. Not always, if some idiiot got in there and did it, but usually 14b Full Floats don't break for example and go forever and ever. So you found a FF and a Dana 44 or 10bolt Front out of a 3/4 ton, strong chance they are 4.10's and a chance they could be 3.73. Either of the 2 gear ratios will be good, 4.10's preferred since you have the OD and likely to run bigger tires. I've seen a set of used 3/4 ton axles anywhere from $250-$500. $300 and $350 are pretty common. Lately though, seem they are closer to the $500 mark. Buying these truck parts is a matter of timing. Anyone will tell you, I've not spent to much for a damn thing on my trucks and parts. And most of what I bought, I wasn't looking for, in fact none of it. I just bird dog CL and when I see something to good to be true, pounce on it before someone else does, or before someone educates them about it.
But, do try to get the rear driveshaft form the donor truck. Yours is long bed right? 3/4 tons didn't come in short bed, so if your long bed and the 3/4 is long bed, you'll have the right one to match the 14b FF length difference, and not have to use a combo u joint, and have a stronger driveshaft too. Usually, the driveshaft can be a deal sealer. Tell the seller if he has it, you'll take it IF he throws in the driveshaft. Most don't give a rats ass. On that A833 trans I bought, I had that guy throw in the front driveshaft and crossmember. He didn't even flinch, and said yeah, I don't need it. Save me a bunch of time hunting those parts down and buying them. (Although I had them already and didn't know it).