Reddit was Lisp for a rather short time before being rewritten in Python. Isn't the story that HN was written in Arc as a response to Reddit's Python rewrite?
HN was written in Arc because Paul liked Lisp and made Arc and wanted a real project to try it. It really had nothing to do with reddit's switch to Python (which as you correctly point out was in it's second year).
HN was more a response to PG wanting more moderation control over the content.
I think it still definitely counts. Reddit 1.0 was Lisp, and deployed as a Lisp service. It wasn’t as if it was some hokey prototype then finally converted for showtime.
HN was more a response to PG wanting more moderation control over the content.