Have y'all had much luck acquiring vintage
computer books/info via
library book sales?
Absolutely. Silicon Valley is one of the best places to be for this.
This is where "vswmoretp" on eBay get some of their stuff.
There is a whole used book buying/dealing subculture around the book
sales out here.
Get to know the people at your local library that handle the book sales.
If you are after mags like Datamation, you may need to talk to them
about saving them for you, since they probably would be recycled
otherwise and not even put up for sale, since periodicals don't sell well.