Can you guess the search query string?

There’s an OLD forum online that doesn’t include a search feature, just an archive of all threads and I’d really like to index the pages, but Sphider didn’t work (pages seem blocked for robots and I can’t get it to browse the site as a browser, rather than as a robot)

Instead: It might have a “search” feature I can use, but I don’t know all the common query strings/variables commonly used by old forum platforms for me to test it. I think it was completely custom made, but you know, there has always been trends in programming

Can you tell?
The urls end with (e.g.) /org_board.show_msg?an_msg_id=1787112
and the main boards page is at /org_board.p_main
Can you guess the search query string/vars?