Below is a scan out of the Canadian Funeral Service for October, 1963 showing conversions of production cars for funeral use by the Automotive Conversion Corporation. I have increased in size the pictures of the Buick offerings from the advertisement for clarity. The layout of the original ad is shown at the bottom. I've never found any pictures of real-life Buick Amblewagons on the internet, but because their parent company's claim to fame was taking a stock station wagon and outfitting it for funeral or ambulance service, it's possible that any remaining Amblewagon's were simply stripped of their upfitted equipment after their service and used as civilian vehicles.
See this CoachBuilt.com page for more information regarding Amblewagons.
Ad as printed.
Source: Flickr user Alden Jewell