I agree with Bill. My 46 had the enclosed driveshaft and when I took it off the truck I found grooves for the spring perch to rotate. The saddle was not attached to the axle/rear housing assembly. It was held between the spring and the axle with the u-bolts. It's all in my shed if you need pictures. I went with and open driveshaft.

1946 Chevy Half Ton
('56 235, '86 T5, '79 Camaro Z28 rear end, working on the '85 Jaguar XJ6 IFS)
1976 Margay Panther X, MC91B