That is effectively what Fender are claiming they now have in Europe (off the back of a case that was not even argued because the vendor didn't turn up).

One key thing here is that the Stratocaster did have a design patent attached, and when your design patent expires, that's it; none of that is protected.

But the guitar was designed in 1954 (and indeed the body shape in 1951, fundamentally, because the Fender Precision bass guitar looked like that first). So the design patent was gone by 1970.

At the time, US copyright did not apply to functional shapes, and most of the core aspects of the Strat shape are actually functional — cutaways and sculpting.

Manufacturers like Schecter were making guitars with an S body shape by 1979. So this isn't new, and it is weird.