I call rip-off! Though they could've gotten the idea from Step Brothers, in which Will Ferrell has a katana sword that is signed by Randy Jackson from American Idol. However! ...
Unlike the White Album signed by Peter Benchley (valuable item, valuable signature), the katana sword is fairly worthless, and was simply what the character had on him when happening upon Randy Jackson. So, given further consideration, it would seem this guy did rip-off Scharpling and Wurster. He and his colleagues should be knocked unconcious and placed in Spike's dungeon.