The Reservatory (motor life blog) has found photos of the "round door rolls" Jonckheere Rolls Royce at a New York motor show in the early 1950's

at the Herb Shriner's Third Annual International Motor Sports Show, Seventh Regiment Armory, 2/54.

http://www.reservatory6.blogspot.com/2013/07/new-york-city-auto-shows-1952-56.html