HanBan,
I looked for the Vang on Beneteau’s spare part site; however , as you mentioned, it isn’t listed. On some items, it will not only provide the Beneteau part number, but will also give you the manufacture part number ( Lewmar hatch numbers). It isn’t a perfect system; however, I have found it to be helpful in most instances.
I have also ordered parts from US Spars; Good customer service. You can actually talk to them on the phone; they are friendly & helpful. As Jim mentioned, you can send the furling drum for your 323 to them for repairs or just order any parts from them & rebuild it yourself.