Pretty much, but each DS can manage all of it's PXE configs from within the PXE Configuration Utility, but yup, that's pretty much what you do. This is, actually, one advantage of how we do things in NS7/DS7. Granted, it's one of the few advantages right now ;-) but it's still one reason why we're moving toward DS7 integration with NS. NS can manage all of those PXE configurations in a single click.
I no longer have a DS 6.x installation available, but I'm pretty sure the drivers you add go into a subfolder of Boot Disk Creator, and you can find them there - in a Custom folder I believe. Once you find them, you'll see pretty clearly the organization. Truthfully, many customers, once they understand this, don't even use Boot Disk Creator to add their drivers. You capture this folder, and replicate the contents to the other DS's in your environment, and then recompile.
Sorry for not having more specific details. I found it once about 2 yrs ago and haven't touched it since, because I now mostly support DS 7.1. :D