Immobilizer issues

[Sinturion]

Hi everyone, I've recently purchased an engine conversion kit from a 2008 highlander.
The person who I bought it off however managed to lose the transponder ecu (dork!). Is it possible to pick up a junk yard transponder ecu with matching key and have the ecu re-register it's communication ID?
I've got these following instructions from the camry FSM, but I'm not sure if it will work with a second hand transponder ecu - or with a highlander for that matter.


ECU COMMUNICATION ID REGISTRATION NOTICE:
The ECU communication ID should be registered when the transponder key ECU and/or the ECM is replaced in order to match it to the ECM communication ID.
The SFI system cannot be started unless the ECM communication ID matches.

(a) ECU communication ID registration (Procedure C): Register the ECU communication ID, after the transponder key ECU and/or the ECM is replaced.
(1) Using SST, connect terminals TC and CG of the DLC3. SST 09843-18040
(2) Turn the ignition switch to the ON position and leave the vehicle as is for 30 minutes.
(3) Check that the engine starts.



Any help is very much appreciated.