I think this is a good summary:
DS: Did you have a patent on the pickup?
LP: No.
DS: Did you invent it?
LP: I'm not saying I invented it. I was the one that way back in the 20's made my rendition of probably the first solid body guitar that was made of wood and seriously was out there not as a novelty, but as an honest to God guitar. I was the first one to do that.
Consistent with what I have read before. Apparently, bluesmen had put pick-ups on their guitars in the '20s, and maybe some in the teens, such that when LP claimed he "invented the electric guitar", he got more than a little pig-piled on. He is saying here that their guitars were a "novelty", and I don't blame him for that as these guys were searching for their own sound, not for a way to mass-produce guitars that only used electronic pick-ups, which no one had done before. So, from a strict sense of the word, did he "invent" the electric guitar? No. Did he revolutionize the guitar-playing world with his designs that made them practical, popular, and reliable? Clearly, yes.