I've a suspicion that mine is almost a prototype Ty, and the one in the brochure is the usual one. The serial number of mine is 4IEB641038. On checking I find my Briggs was made in March 1963. I suspect the edger was made very early in 1964, and may have been only their thirty-eighth attempt. I raised the subject with the manufacturer, but their response was just to refer to it as "this old edger", which convinced me they weren't interested in the subject.
