I can probably get access to those service manuals at work. I’m a tech at a GM dealership. I’ll see what I can find.
If not, they're all available here for free. If you don't see the year you're looking for just keep scrolling, other members have added missing years over time. I know '97, '98 and '99 are there somewhere.
https://www.gmt400.com/threads/88-98-service-manuals.43575/
I own a paper set of these for my '97s, but sometimes the PDF copies are nice just because you can CTRL+F and search for a specific word or term.