Thanks RaraK, I ended up swapping the small eproms around, could have just as easily flashed the old info onto the replacement ECU I suppose. This worked great and the car is back on the road.
For future reference, if I didn't have the old original ECU, how could I disable the IMMO within that eprom. I can post the dump from both box codes if needed.
Thanks for the help everyone!
You can either copy/paste immo stuff into new eeprom to avoid any possible issues with new ECU using different EEPROM regions for different things than older ECU or flip two bytes around to disable immo altogether and then hand modify checksums or run the file via the checksum calculator program I just posted yesterday in this forum.