Nice selection of their guns, here.
Barrow weapons
Closest thing to that piece of junk would be the break-top IJ that Bonnie smuggled into Clyde, when he was in the city jail, early on in their relationship.
Interesting bit of trivia, to me anyway, on that site. I've always heard that they did not use Thompsons, preferring BARs. An interview with one of the gang member said they tried Thompsons, but the guns were, apparently, all lying on the floorboards of the back seat, and with all the bouncing around, the drums got dented, causing jams. The BAR 20-round box did not have that problem.