Well what good is that? You can't tell if multiple IP,port pairs are from a single client or multiple clients.
The nat device will have different source ports for two connected clients.
It would also have different source ports if the client is using random source ports as well. So two client connections from the same host behind NAT would look exactly the same as two client connections from two different hosts behind NAT.
Hence the authentication on the web backend and the unique 64bit client id.