I've been able to fix PXE driver problems in the past by copying the
SYS:TFTP folder off of a ZEN 6.5 server over to servers that were installed
with older flavors of ZEN (4.0), and right away PXE clients receive the new
loadlin, linux.1 and linux.2 files, and thus recognize newer hardware.

Looking through the SYS:TFTP folder of a ZEN 7 server, however, I'm not
seeing these same files - initrd is still there, but does ZEN 7 download
different files to PXE clients, and if I thus needed to add driver support
(previously done by recompiling them into a new linux.2), how is this
accomplished now?

The quick question is simply: can I copy the SYS:TFTP folder off a ZEN 6.5
server to the existing PXE server, and assume that PXE clients will
automatically gain access to the ZEN 7 driver database?