To answer your question would require a lot of looking at the various barrel drawing numbers and comparing them to the one shown.

I can tell you one I saw that was probably "field expedient" and was very different from the standardized version. I was at a gun show in Pennsylvania circa 1978 and an 03A2 was on a table for sale. It had an adapted M1919A4 Browning Machine Gun (BMG) barrel. If you are familiar with the 1919A4, the barrel is bull shaped, quite thick in outside diameter. There was an adapter inside the 03 receiver, so it could take the different threads on the BMG barrel. The rifle weighted a small ton and I looked it over for several minutes (I could not afford it in those days). The rifle had quite a bit of wear and you could see it was not something made up in somebody's garage. The owner had the 37mm Anti Tank Gun pictured, with the 03A2 installed. He had sold the big gun and was looking to get rid of the sub caliber device (03A2). It was a treat.