Your 5 brush powerhouse looks good, but I'd remove the plastic tape and give it a coat or two of "LIQUID TAPE". This is like a rubber coating and dries fairly quickly. A second coat can be applied after a 5 minute wait. Thankfully no one has foolishly turned the commutator. How hot is hot? From working and engine and radiator heat, they will get pretty warm, but you should be able to lay your hand on it.
Use care around that Bakelite brush holder, as they are brittle and hard to find.
I've repaired cracks in them with JB Weld, but nice ones are better and very rare.