Thank you all for weighing in on this. For some reason I have not been getting email notifications on this thread until this morning so I thought it had died.
I was finally able to get the Win 8.0 32-bit drivers for the new Optiplex systems from Intel. Intel included the new driver set in the "IntelProset 20.4.1" configurations. (The NDIS63 folder contains the Win 8.0 drivers.)
This driver set enabled me to get WinPE 4.0 working with the 8.0 configuration. There was no problem with the PXE boot process but the drivers were not available for the Win 8.0-based WinPE 4.0 to connect to the network. We are back and working now after adding the driver to the WinPE 4.0 image.
We are in the process of getting GSS licenses so I hope we can get that upgraded soon.
Thanks, Ian, for providing the Symantec link for the drivers. Since I hadn't gotten the posting notice I went down the Intel path.
This issue is resolved for me.