I've read up on this topic here. What I learned is basically what you already know, but remember an NOS CB400F bar is still available from some sources and will be of much better quality than a standard "emgo" superbike bar. The chrome is apparently much better, better metallurgy, and of course pre-drilled wiring holes, and holes for the pins that hold the switch housing.
I really don't think it would be a big deal to recreate the wiring holes in a new set. Seems like there wasn't a huge difference dimension-wise between the two, so I don't know if riding position will be much different.
Of course, the emgo bars are much cheaper than NOS Honda bars, so that would be a big factor for me.