Much as I love making wiring harnesses, I will never know enough about electronics. Having said that, from the little I know those thingies are the cores for your secondary coils, or some such, and yes, they are earthed. I am sure someone will correct me if I am wrong. Here is some coil stuff I came across https://www.motorcycleproject.com/text/high_perf_ignition_coils.html
I cleaned mine up with some wet and dry paper, then put some dielectric grease on the original coil's. But i don't think they are earth's, as the coil on plug conversion didn't need any earth's, it rely's on the TCI switching on/off for the earth. If it only has a single wire to the ignition coil then yes they're earth point's
Yea just going by the fact they are metal and have those metal clips held on of course with metal bolts to a metal bracket that looks to have no rubber grommets or such in the mounting points to the frame .... going on all that metal to metal contact led me to question it And those pictured are the ones off my bike ... and there was alot of surface 'rust' in that area on all those mounting points
No, I think my67xr has it correct. There is a power wire (usually red) and an earth switched wire from the TCI (green or black) that causes the coils to fire. Won't hurt to clean them as the mounts/bolts will take a bit of heat from a hard worked coil.