No, it's a completely different axle. The diameter and spline count (your D44=19 spline, AMC20=29spline) where they engage the spider gears inside are different just for starters.
You don't have to buy a complete new axle assembly either. Just get a replacement for the two piece axleshaft. The Dana 44 two piece rear axle is much stronger than the AMC 20 and isn't nearly as prone to failure.
If there is anyone out there still making a one piece replacement for the D44, I can't find them. Moser or Dutchman may be able to custom make one for you.