Overriding Component Copy/Paste

I'm not really sure I fully understad your question completely, but here is my put :

Unity has a unique instance Id for each Object, so you need to create another serializable variable, somewhat called _cachedID that set to instanceID

And then when the copy occurs the instanceID of the copied Object should be different from _cachedID, check this and you know it's being copied.

Knowing it's being copy, you can regenerate your uniqueID or doing anything the way you want.

In Unity, there is no adequate way to do this. Manipulations with InstanceID will not give the right effect, because it changes when you exit the scene, which will generate false alarms. You also can not focus on FileID, because it works only in the editor, but it is unique. You can not hope for it either because there is no collback in which you could overwrite this data. Callbacks Awake, OnEnable, will occur earlier than you need. There are scenarios in which the unit is overwritten the data after (for example CopyComponent in the context menu). You can not use OnAfterDeserialize () because you can not get rid of the FileID in this callback, or check Application.IsPlaying - all these calls are blocked there, but they are needed for high-quality processing of situations. There is no way to solve this issue fully, until Unity creates subscriptions to such situations. And she will not create them, because the problem is rare.