I would guess that some time over the past 58 years, someone made a roof rack out of iron pipe. While clever in the use of low $ materials, the pipe threads are a weak link and that is where the pipe will break. That is my guess as to why only the flanges are left.

I would remove the screws and weld the holes shut


The problems we face today can not be addressed at the same level of intelligence we were at when we created them - Albert Einstein Or with the same level of $ - Me