When I lived out there but not at Bethel, I just had a Bethelite come down to sign me in and spent many hours in the varous Bethel libraries...I loved the older books. I could not check them out but then you can't check books out at the KH library any more either.
If you represented yourself as an ex-JW, you probably would not have access. If you had some sort of credentials as a researcher, there might be access.
Interestingly enough, I had no interest until I watched a show where an ex-JW said that a certain book was no longer in JW libraries because they had been ordered to burn them. So I went checking and I found several copies still in the Bethel libraries...as well as older JW personal libraries. Makes me wonder what the ex-JW meant. The book: The Way to Paradise by W.E. VanAmburgh. It is an old book and the paper used to print it has not held up over time. But when I questioned a person from that time (Bible Students then), they never heard of being told to burn any book let alone that one.