Not exactly, it was used before that as well, I don't have time to find references for this right now as it's Dec 31st and I'm going out in a bit, but will upda

Not exactly, it was used before that as well, I don't have time to find references for this right now as it's Dec 31st and I'm going out in a bit, but will update the article with them later. "Open source" probably got coined/invented multiple times independently, which is not surprising since "open" was very common as well, or perhaps the OSI folks simply forgot they heard it before (human memory is not very good).