I apologize for my confusion, I hadn't fully caught up on this thread after making it back from camping in the forest with my sons Scouting troop last night (largest troop in the district, 80 campers this weekend); I was still working with the OP statement of
Our tech guy said that he found in the source code that the forum is v 18.104.22.168 -- copyright 2003 AD.
But in either case, the redirector scripts likely won't work for him, as I've recently tested them on a vanilla UBB.threads 7.6.2 on PHP5.6 and 7.0+ and all requests just end up forwarded to the forum index; and since very little users utilize the scripts, and the vendor is not contracting to have them updated, it was deemed a back burner project until the PHP7 updates and testing are completed.
I would advise upgrading the UBB.Classic install as soon as you can, as there have been major changes in responsive layouts and SEO that will benefit everyone in UBB.threads7.
The OP may experience some missing content errors from search engines without working redirector scripts, but I offer a 3rd party a Sitemap script UBB.threads Sitemap
and UBB.threads Member Data Sitemap
to aid in search engine discovery.