The Hobbs Raceweight changed its lug design a few times between the model's inception in 1930 until it disappeared from the catalogs around 1953. The lugs that were used through the post-war years until 1951 or so, which looked similar overall (the later ones having scalloped edges around the front of the head tube rather than the smooth look shown here), were apparently a proprietary design or were heavily modified from their original form.

-Gregory