Support article KB52620 - How to manage ePO agent GUIDs when creating an image of a Mac computer
This article described how to do it for Mac.
The principle is going to be pretty much the same for Linux, just with slightly different directory paths.
Basically install the agent and then modify the registry.ini file:
Find registry.ini for editing.
Locate and delete the following line:
(where XXXXX is the unique GUID for that computer)
Don't let the machine connect back to ePO before committing the image or the guid will be fixed again - you only want that to happen after when the image is used normally to make a new machine.