A quick look for a replacement yielded a modern equivalent. A Precision 476838 Seal was a perfect fit. It is a double lip seal and should yield adequate protection. I doubt they will last over 60 years though.
The old seal is easily pushed out with two sockets of appropriate size. The new seal is pushed just as easily with one socket. If the seal becomes cocked in the hole it is very difficult to push. I chose to use my drill press as a light-duty press for this job since it is easy to line up for a perfectly even press job. (drill motor off of course)
Remember the castle nut of the seal assembly is LEFT-handed, just like the axle.