This all was pulled by a friend of mine who died a few years ago. He was particularly talented in old Buick restorations, once winning Best of Show overall with his 1953 Skylark at Flint's Sloan Museum Summer Fair many years ago. One of the other Buicks he restored was a beautiful 1957 Buick Roadmaster convertible. These parts, I have no doubt, are also the same for Cadillac and Oldsmobile of similar years.
Back in the 1960's and 70's he would prowl junkyards for extra parts for his projects while they were still available before all the junk yards began crushing when the prices for scrap metal climbed so high in the 1980's, and stayed pretty high after that though fluctuated with the seasons.
I also started buying parts in junkyards beginning in 1965, to keep my daily-driver 1939 Buick on the road. Back then, cars and trucks in the 1930's and newer were common in the scrap yards. Any of us old car guys in our 70's and 80's can tell you stories.
Very good to excellent condition but untested. This is just how I found them in a cabinet in Bob's garage at his estate sale a few years before the pandemic.