Last '69 Swinger 340 built????

My 69 swinger 340 registry is growing daily and I have a bunch of new cars to add. Just found and documented what might be the last '69 swinger 340 built! For the longest time there has been a swinger vin'd last six of 450,*** which was thought to be last built but I now have a confirmed swinger 340 with a vin of LM23P9B451,0xx built on 718 (July 18, 1969). It's a B7 stripe delete car with only options of extra molding group and a vinyl roof, that's it.

Does anyone know what the last day of production for the Hamtramck plant was in '69 model year???