Trademarks are a fundamentally different kind of IP.

With copyright and patent, the creator of the work is being protected. But with trademark law, it's not about protecting the content of the IP as such. It's about protecting the consumer from being misled into thinking they're getting the real thing.

And given the guitar market at large, with about ten thousand different guitars in the general shape of a Strat, it's pretty much universally known that the name on the headstock is what you have to look at to differentiate. So long as that name isn't misleading, I have a hard time imagining how they could make a case of it.

I mean, if the headstock says "Fernando Stratoblaster" or something, then MAYBE it's a little confusing. But my guitar, a Kramer Focus 6000 looked very nearly identical to a Strat (the edges are less beveled, the headstock is pointier, but at a quick glance...), but it quite clearly says that it's NOT a strat. Nobody's going to be fooled despite the striking similarity in shape.