Hmmm, that can only be part of the story.

I have one of the circle of holes Colnago Super bikes (1968 or 1969?).

Mine came with clover stencils (no decals, as far as I can tell). But, I didn't buy it until 1982, and I don't have the history of the bike before I purchased it, or if I was told, I don't remember. So, there is some question whether it might have had a factory repaint. Bike purchased used in Parma, Italy.

Anyway, while it had the circle of holes on the bottom bracket, it also has clovers on the main lugs.

So, while Colnago may have chosen to redesign their stencils and decals after 1970, the clover on the lugs would have pre-dated that redesign.