I think that the first library is InstrumentCS_logic7 which is only instruments. The second one was Logic 7 Channel Strip settings which has Instrument and several other settings in the same folder.
I was thinking that the one for Audio which is Logic 7 Channel Strip settings would only load channel strips for audio instruments which are not software instruments, audio tracks being those for plugging in an external Audio instrument. I think the instrument folder is the same in both. I think track is the one for the Audio Instruments.
I am a little curious if the Instruments such as the Woodwinds in Logic 8 or the brass existed in Logic 7. I didn't have those on Logic 7. They open up with those new instrument even though they are Logic 7 Instruments.