I have no idea how I could *prove* that the engine in my car has 6 cylinders but it's in the description of the model (and no, no ignition cables to count as it's a Diesel engine).
In your case you have diesel fuel line/rail .Just busting your chops :)
But ede bought up the point the datasheet and the fact that you do not have asymmetrical routing enabled should be good enough.
also to edit, if the auditor becomes pain, you can always make a configuration dump send it into tac and have them confirm 1> it's operating in stateful mode 2> and uRPF anti-spoof is enabled
I had to do just that for a PCI auditor for a similar audit where they didn't take the word of 4 local engineers that our firewalls was acting like a firewall, smh.
So they accepted the word of the TAC.
Ken Felix