Maybe they have a design patent. Until earlier this year, you couldn't get a patent on something that already existed. But, the law's been changed to "first to file" rather than "first to invent", so existing "prior art" has been more or less lost as disqualifier. Thanks, Obama. You're a swell guy.
What that means is if you invented something 13 years ago but didn't file for a patent, then last year I saw it and filed for a patent on it, then I get the patent and I can sue the snot out of your for infringing on something you invented.
As you might imagine, that is one super-stupid way of handling things.
You'll also notice that the timing is right for Gibson to start chipping away at all the folks who've been using their designs for the last 50+ years.
It's also absolutely ruining the software/hardware business, among others, unless you're a monster like Cisco, Microsoft, Oracle, Sony, Google, et al.