Christos on that episode is known as Gryphos on the 1919 and biggerhammer websites. He's been importing .50 cal Browning kits for years, both M3s and M2s and I wouldn't be surprised if that was one of his kits. He truly is an expert on that gun. And yes, although the parts kit was a complete Browning M2, it had a semi-auto only sideplate with a denial island per ATF regs. He milled away the denial island to allow the unmodified full-auto parts in the M2 to fit. As a Type 07 manufacturer, he can make those all day long, but it's now a post-86 so it can't be transferred to civilians. The nice thing about the M2 is if he decides to sell it, he takes off the sideplate and destroys it, and he can sell the rest of the gun as a parts kit. He'll probably get almost all his money back too, although 6K seems a little high for an M2 kit.