The mechanics of the machine remind me of the Seraph vendors in BL2: a limited list of items that can appear but the number of each item and their parts can vary widely per visit.
I was hoping to see M4/M6 gear in the machine and that they would be available on lower and non-mayhem levels, as a sneaky way (it’s a black market after all) to make those guns available to players in those modes if they’ve got the cash, and the time to seek out the machine. 
Who knows, they may still do that in the weeks to come.