You need the Realtek kext to get LAN working whether or not you have Ethernet built in injector set. However unless you set Ethernet built in to Yes, you won't be able to use the App Store.
Thaks, but that does address the bug I encountered. My delimea was how best to set the ethernet builtin property and inject graphics properties. I have managed a fairly satisfactory workaround so my immediate crisis is over.
Thanks for all assistance provided.