Well, I went back though my old catalogs and magazines. It appears there is some variation in headbadge styles, depending on the model. However, I did find a single example of what appears to be arbarth's style of head badge in a a 1973 road test of a Le Champion. Unfortunately, its a hind quarter pic, but the badge is definitely very thick, with a flat top and long, straight side. I also have an early, undated, catalog showing a Grand Record with a sticker headbadge. From what I've read, Moto was not nationally distrributed prior to 1972, so the catalog is probably a 1972 or 1973. The round headbadges were in use in 1974 and the 1975 Grand Record definitely had a round headbadge. Since the only evidence of this style of headbadge is from 1973, I'd say abarth's model is probably a 1973.