it comes down to what one is trying to prove. If the OP does not trust the seller only a DI of the original demo track would help. If the claim is that a profile sounds different on any PROFILER regardless if all of the global settings are exactly the same on each unit this will easily be debunked by reamping the same DI using the same profile on several PROFILERs. The outcome is already clear-since the PROFILER is a digital device the results will all be identical.
... provided no fairy dust was added to the demo recordings.