I was not there so I cannot guarantee this is correct - nonetheless, the Hill brothers from London say it is verifiable. Do you know what violin Mozart played? It was not a Strad and it was not a Guarneri. It was not a Kloz and it was not a Stadlmann. It was not a Montagnana and it was not a Storioni. It was not a Stainer either. It was a Pietro Antonio Dalla Costa. The violin on the left is a Dalla Costa, but it's not the one Mozart owned.