Yep, you're right. For OS 8.5 users, 8.6 is a free upgrade, but 8.1 owners have to get a full retail install CD. I know that because i upgraded to 8.5 back when it first came out, and i know that OS 8.5 was a paid-for upgrade (and 8.6 was free after that), as was OS 9.
Either way, not a bad haul...apart from the Norton CD [xx(] ]'>