I believe that the “black” is not just the usual paint but rather a bitumen (tar) based product intended for corrosion protection and damp proofing. I suspect that if you warm it up a bit you will find that it softens.
If you don’t have spark after cleaning the contacts
take the points apart and clean the individual parts.
Those sparkplug boots look to be after market from
the time. Possibility Bakelite. I’d be surprised if
you could find another pair of them.
Tubs