Anything is possible. Maybe this was the least expensive Model 600.
Jack Sim is working on another pump book. Last I heard was he has 1/2 as many as the 1st book & pictures with no company names.

On ebay there is an AMERICAN clockface 550, that is not in the 1st book [the computer 550 is].
Dick

Reproduction/Fantasy Cans
http://i124.photobucket.com/albums/p2/oldegaspump/AllCansMASTERTHUMBNAIL_zps4bfdbbc7.jpg
Rnd Can Re-lids