Hiya Rammjet, thanks for looking in on this.
So the vendor id was the same, only the device id was different, and it appears that several others had the 1092 dev id with this card. I feel confident in saying I followed the instructions of the link from your post properly. The plist certainly looks correct, I did all the cache clearing, permission repairing, and rebooting.
Just can't get the built in ethernet option in system preferences --> network --> Network Port Configurations to be available. Lights still green in the back though

I also tried using the kext
posted by caladan1810 here which instructs to place the AppleIntel8255x.kext at the /System/Library/Extensions level rather than at /System/Library/Extensions/IONetworkingFamily.kext/Contents/PlugIns/
So far, I've double checked that caladan's plist contains the proper string for my device, and it does.
I placed it at the level he suggested, removed the existing one way down inside the plugins directory, (made a backup first of course) and did the manual reload per his instructions. OS had no issues with it.
Cleaned up and rebooted, but under system preferences --> Network settings --> network port configurations has Built-in Ethernet greyed out. There are also ethernet adaptors at en1 and en2 and firewire, but none of those are actual devices I can get on the network with.
so the next thing I did was try moving caladan's kext inside the IONetworkingFamily/Contents/Plugins directory, but had the same behavior.
After thatI went back to putting the original kext from the install in the plugins directory, with the modifications from the link you provided in your original post (where I started three hours ago) and just for grins, rebooted.
Over to system preferences --> Network settings --> network port and lo and behold it recognizes a new card. So built in ethernet is still greyed out but I'm online using PCI Ethernet Slot Ethernet.
That's a happy ending.
I left all of the above in case someone comes across this post in the future and is at all helpful.