I have posted pictures of the fuel sender/pickup access hole in coach 1046 in this album:

http://www.fmcowners.com/mbbs22/photos/photo-thumbnails.asp?albumid=105&useralbum=33 

I also give dimensions to locate the hole so that if anyone desires to create such an inspection hole, they know where to make it.

FMC provided the access hole in coaches from #700 and up.