This is probably a stupid question, but since I have an msd box and coil feeding my distributor is the part on top of the distributor that would typically house the coil empty in this case?

I'm upgrading some ignition wires and thinking about the cap as well, but I don't really know what to get. Do I have to stick with the regular HEI cap type that has that casing for the built in coil? Or are there caps that work for this situation that just omit that part all together?