My mom used to say they (Libby's) were squash too, and she used it every year. I think it's one of those rumors that go around. I don't believe it though - if it were squash they would have to declare it on the ingredients.
I did my own pumpkins last year from pie pumpkins I found at Tesco. It worked okay, I had more problems figuring out the crust and finding a pie pan (I'm using a sandwich tin, whatever that is). It was a pain but nowhere near as hard as making our own cider (with a blender and clean thin tea towels to squeeze it!). I can't afford to ship Libby's in - the cans are too heavy!