There is really not much to tell except the tire tried to demount itself, explosively. I had chains on it and made sure the lock ring was centered but as I was airing it up boom. The chains stopped the lock ring from sailing into the sky.
Like I said if you make sure the rim and lockring are in good shape and take safety precautions it should not be a problem.
If you are interested in changing to tubeless tires you will probably have to change to a 19.5 size.
http://www.stovebolt.com/techtips/wheels/describes what is needed much better than I. Make sure the center hub is the same size as well as the bolt pattern and it should be fine.
As it happens I may be in the market for a couple of original 20s that are in good shape. Unfortunately I can't really drive across the country on a whim.
