Thank you, Keith, though I don't smoke cigars!
As Keith mentioned, Tom provided some interesting information, and a few photos. Here's what he mentioned in an e-mail to me:
" In fact, it is a 1950 Barnette-Pontiac Series 200 "Utility Car". Barnette produced three Series in 1950 on both the Pontiac and Chevrolet chassis. These were, naturally, conversions of the Chev or Pontiac sedan deliveries. As I said, they were available in three series - 600, 400 and 200. The 600 Series Pontiacs had a wheelbase of 156-inches while the Chevrolets in that series had a 151-inch wheelbase. The 400 Series Pontiacs had a wheelbase of 144-inches and the Chevrolets a wheelbase of 139-inches. In the 200 Series the Pontiac wheelbase was 120-inches and that of the Chev 115-inches. A 200 Series Pontiac Utility Car in standard configuration listed for $2,749 while a Chevrolet version went for $2,545."
Ed, I'm not sure what you are comparing in your two photos, it looks like you have a Barnette and a Barnette. Indeed, I wonder if the white over red LWB ambulance in your photo might actually BE the one in the ad I posted. A lot of similarities, accouting for the ravages of time...
Annnnnd, here are the Barnette factory photos that confirm this car's identity as a Barnette 200 (reduced in size from Tom's huge scans).