I don't believe the online catalog from the MOCO site contains the complete parts breakdowns and diagrams.
I think you will only get complete parts information if you buy the parts manual. And, I have never found complete information online.
That leaves buying it from the dealer, or possibly finding it on ebay or a location like that. I have noticed quite a few sportster manuals on there.
Believe it, the money spent on service, wiring, and parts manuals is like money in the bank, if you intend on doing any of your own maintenance.