So the current situation is that despite my past posts about fixes to WSS 2.0/2003 Full Text Search, both my QA and Production environments have Full Text Search enabled, but are/were only returning results for content that pre-existed the fixes.
The Full Text Index actually existed in the SQL Server Content Database (for WSS content), and the MS Search service was running properly on the SQL Server.
Reviewing the best discussion of this sort of thing that I know for steps I might have left out, I found out that even though WSS 2.0/2003 says it’s got Full Text Search enabled, it may not in fact be enabled.
So you go to SharePoint Central Administration, then click the Windows SharePoint Services link on the left side nav bar, and then click the “Configure Full Text Services” link and even though the checkbox is already enabled, click “OK” anyway, and let the changes be applied and go check the functionality of your search against new content.
Update: This only ended up working for me in our QA environment, which is apparently different in this respect from our Production environment (still b0rked). Oh well, there may be a call to MS support in my future if I continue to be stumped.
And scarily, for me, Full Text Search started working properly, even with new content.