Hello D-D
When Airbus makes and aircraft, they write a set of FCOM manuals that are "Airbus". If your company want to amend these, they approach Airbus and the manufacturer is happy to change any pages at a cost (I hear about E300/page).
Thus, to answer your question, Airbus supplies the originals, individual companies are at liberty to change them as and how they see fit. Normally, the only things that companies change are the Normal Operations in the FCOM 3. Most companies, mine included, find the cost of changing the Airbus SOPs to be exorbitant, so either rewrite them as a stand-alone doc, or insert them in the FCOM themselves.
Airbus would probably be able to supply you with an original version if you ask. The other posting mentions the Airbus rep - this is the way to go - I am not sure the manufacturer will supply you with the original if you are not an "Airbus operating company" employee.
Hope this helps