Ricky,
That's the part number for the instruction sheet, which came with about five different items. It's best to get in the habit of providing the 6- number off of the end of the item's box.
The pantograph insulators for the MU cars are available from Lionel: 610-8304-075. I'm not sure why your pantographs would be falling off -- all the insulators do is provide stability. They don't help with securing the pantograph to the roof.
Lastly, you'll need to provide more information with the operational problems you're having. Which lights don't work -- the headlights and/or interior? Also, are you working on a powered or dummy unit? Are you operating in TMCC or conventional modes?
TRW