I would pass on both sets until you find out exactly what they are. Any axle as old as the Jeep set is going to have low spline counts. More splines=strength.

Looking at the width though I'd highly suspect they were swapped in from a Chevy. No Jeep axle was ever that wide and no Jeep in '64 had disc brakes. If you can find the BOM number on the axle tube just to the right of where it enters the center section I can look it up for you (if it's not too old).

The easiest swap under that YJ frame is going to be a Wagoneer axle from '74-79 if you want passenger drop front diff. Find the rear axle from any '80-91 Wagoneer for a centered rear diff. The width will match and so will the bolt pattern for the wheels.

Don't go throwing money at turds cause they look like they will work.

I've never paid more than $100 for any complete axle (unless we start talking front Dana 60s).