do you really want to know? If so, I'll show you how deep the rabbit hole goes...
(as for knowing diesel, I've been to the B.H. distributing warehouse several times and know many of the top reps... I also own enough pairs personally to know fakes when I see em. There are a lot of subtle details that fake jeans will not posess. On the zathans, there is a small circular logo thingy above the V on the pocket... fakes would not likely have this.)