My mother has a bunch of WTS books from around the 60s to present, including almost every one of the magazine collections from 1975 to at least the late 1990s. Many of the books had pretty well-worn covers, but the interiors are probably good.
I doubt I'll get my hands on them. For one, I have no interest in them. Two, when she passes away my sisters will be more interested in dividing up the spoils than I will. None are JWs, so I have no idea what they'll want to do with the books. But I figure there are a lot of older JWs with pretty extensive collections, and as they pass away their non-JW kids will either throw them away or make them available.