Right now Gibson is trying to sue Dean Guitars for copying a couple of Gibson’s models. Unfortunately Dean has been making them for 40 years+ and the headstocks are different. Gibson only filed a couple of years ago. The US lawsuit continues but Gibson just got its @ss handed to it in German Courts.
Gibson is also trying to say they own the guitar shape you see on virtually every acoustic guitar. Good luck with that one.
Gibson’s quality went in to the tank years ago and instead of fixing the issues they decided to sue everyone who stepped up to fill the gap. When $500 similar guitars are better than $4000 Gibson custom shop guitars you of course sue the competition, right?
Gibson does not have a case because, if the the facts are as presented, they let someone use their design for 40 years.
At that point they can not stop anyone from using it.
Defend or lose.
That is why fanfic is such a murky area.
You like our stuff! So much that you want to make up your own stories set in our universe! That is great! Now, stop it or we will have to sue you.
Back thirty or so years ago the rule was, do not sell or officially bring it to the attention of the copyright holder and you were ok. Now with on line publishing and blogs it has really become a mess.