The Serial # says it's a 78 model and that looks like a 78 model. They had high idle switches and the larger black face plate with the amp gauge in the bottom center of it. I do agree the numbers look much bigger then any I have seen. Maybe they changed the faceplate and that was the only size number stamps they had.
Yeah, the numbers are really large compared to any I have seen and deeply stamped too. The serial almost looks like it was miss-stamped and the last 7 is almost superimposed on the second last one. Almost looks like 5 digits instead of 6. Weird.
I see this machine on the craigslist.org/ S Francisco/bay area CA. a few minutes ago and the owner is looking for a "162 continental engine for he's machine" and he show the pic of this welder machine. "better be carefull"