While the graphics are curious and original and or from a factory repaint...the lugs suggest earlier, these lugs are the Rexart financed Mario design initiated, (never approved it seems and or used by Mario), a bit too crude, the shapes are a simplification of the Mario modified Bocama lugs. Often back then (1980's) pre digital production, a tooling designer would insert a circle instead of a developed curve, easier to cut, but leaving the design trashed. These lugs are investment cast, with cut outs done after casting.
The BB shell points later, I do not know when. 1987?