I think we've been through this before, and came to the realization that copyright means you simply cannot copy the pattern and sell it. Maybe a bad thing to do is to use it and make things to sell that are exact copies of what the pattern looks like and not give credit to the pattern maker.
BUT I suspect there are lots of pictures still in existence of old quilts exactly or a lot like theirs, made before the pattern copyrighters were even born, that obviously puts that pattern in doubt. Quilts have evolved in different states and countries over time, and lots of women have had the same ideas of what is lovely and put those ideas in their quilts.
From what I've seen here, lots if not most quilters put their own ideas in their quilts, while more or less following the guidelines of the pattern maker, who we know did work hard trying to make their patterns lovely and accurate.
There are a lot of comments in the past here that can still be accessed on this matter, for and against lots of ideas on this subject.
I think that if you make a quilt and show it, you really should give the pattern maker credit for that pattern. And also give the LA quilter credit, since that is an art form in itself. Otherwise, all that work on the quilt is the MAKER's work and no other person could duplicate it. Quilts aren't clones, (Walmart quilts excepted) I don't think anyone can or would want to make clones of their quilts, except perhaps in the case of making them for twins, and even then there should be some small difference to set them apart.