well, are you sure you had permissions to read that file (eg be root or whoever owns the file)? some files might seem to be empty if you can't read them..at least, if you use some texteditor to read. dunno, though...
I don't know about local1---local6, since I don't have them :P but as long as I know, the rcX files are run only on runlevel X; for example, on runlevel 5 only rc5 is run, and not others. why else would there be different rc-files for different runlevels?