And the answer is that nobody besides DIAC will be able to give you a correct answer with 100% certainty.

If you file online, DIAC asks for scanned images of the original document. If you do a paper filing, notarized copies are requested. Whether or not one notarized by a lawyer will probably depend on your country also.

It's just best to ask DIAC, see this: General Skilled Migration Pre-Lodgement Enquiry Form