Hi,
The whole case is held together with countersunk black hex bolts, the only rivets used are those holding the motherboard pci panel to the back case panel, and these are black, but on the next case will be countersunk too. The hex bolts allow the case to be completely stripped down if need be.
The powdercoat is simply satin black, im not aware of what the actual RAL no is tho, i can get a quote for powdercoating if you want your case done.