It was astonishingly futuristic. And that astonishment took place for the first time for many people when Life, a leading American general-interest magazine, published photos of the car. This happened in late December of 1950 when the 1 January 1951 issue appeared in mail boxes and on news stands. The LeSabre public announcement, for that's what it amounted to, appeared in an article about General Motors, king of corporate America at that time.
Below is my scan of that landmark image along with some publicity photos of what appears to be a LeSabre mockup.
Some puzzling items: Only one functional LeSabre was built, yet the Life image shows two cars, neither painted its normal silvery blue. My guess is that the upper car is a detailed mockup. Note the lack of chrome on the rear bumper: the real LaSabre had chromed bumpers and trim. The nearer car has a chromed front bumper and grille, so it must be the real thing, but painted like the mockup and not yet in silvery blue.
Knowledgeable readers are urged to correct me in comments if my speculations are wrong.