I beg to differ with you ..A 1962 Impala 2 Dr ht only had the square or formal top. A 61 Impala had the large rear back window that went over the back seat….as did Pontiacs, Oldsmobiles, and Buicks which were never ever considered “bubbles”, it’s why the 62 Bel Air got the nick name that bled over to the 61’s. I have no idea where or why 59-60’s ever got the name but who ever did it was not alive or driving them… 55 Ford Crown Victorias had one of the first thin top post large which carried over to the 56-up Victorias ending with the 61 Starliner. All in your vision and opinion I guess