Thanks for the response.
What you found is a Perl front end, but was written for the 3.1.x version of mnoGoSearch (udmSearch). It performs SQL selects on mnoGo's database to obtain search results. The PHP front end, as well as the older Perl front end that I referenced, used mnoGo's libraries to obtain search results. I believe that to create a Perl module to function like this would require the use of h2xs and some knowledge of C.
Maybe I need to learn h2xs and develop a new Perl module if there isn't one available. The other option is to update the front end that you pointed me to by modifying the SQL to use the new mnoGo table structure.