spark plug boots

Yeah you are correct about that. It certainly looks like someone used chainsaw plug boots. 

That is not an OEM. It would be hard plastic and looking into the end where the HT wire goes you would see a small screw like fixture. The actually screw into the HT wire. That is not a resistor boot. Your bike should use removable tips on the plugs. Like mentioned you really dont need an resistance in the system, unless your running an M unit or have a high dollar ignition that might get interference from the spark.