are any of these clusters worth saving?

That was my guess too, but I haven't confirmed it. I had an 85 Chevy that I hated and I seem to remember that cluster from that truck.
Funny, the only Chevy I ever owned was a 78 K5 blazer, it was a rust bucket and the trans went bad more than twice even after I paid good money to rebuild it. Cant say I hated it but it was close:)