Based on your SN, your Willys was likely made in March or April 1950. The Dana 41 is correct for this time frame. The Dana 44 starts showing up on the 3A in late 1950.
I am trying to figure out the attachment of the rear brake line that goes across the rear axle. It looks like there should be a bolt hole in the top of the differential but I cannot find one.
The preformed brake lines did not come with clips. I would think that it should have a clip that goes behind a cover bolt (like the front line) and it looks like it should have three bands to secure the line to the axle.
Can someone post a picture of the clips or straps or what ever is correct.