The LOC-NFR is specifically for film, right, where the LOC in general is for any copyrighted works - film, video, audio, print, etc.?
As far as them coming to you for info, the only thing "sad" about it is that they've logically tried to get the necessary info direct from LFL and are probably getting stonewalled on it, so they had to look to other sources. They're probably glad you're out there, as there are probably other films in the archive (or that the want in the archive) that they can't track down better sources for because they're not as well documented or researched.
You're probably more valuable to them than you think.