Fake Roycroft occasionally shows up on eBay and elsewhere. These include pieces that are clearly not Roycroft in design or execution, as well as more convincing forms that I would guess are Mexican copper. I have seen these "Mexican" pieces (actually not unattractive) not only on eBay but also at major antiques shows being sold unknowingly by reputable antiques dealers.

Here are a couple of photos of fake Roycroft vases. The first photo includes a pic of the fake mark on the bottom of that vase. Not only are the forms and hammering wrong, but that mark is a joke. Beware of this junk!: