I would think the barrels were already painted, and the pre-painted chrome centers welded to them.
So, 2 different kinds of paint - the barrels being the cheap deal - seems likely.
I don't have any handy to verify, sold my last original '69 many years ago.
Center blackouts were a semi-gloss (aka satin).
The red drips on the backside could be from the red paint they put on the face of the brake drum for road-wheel cars.
My originals also had brushed trim rings, not the polished ones that you see nowadays.