that's a bit of a surprise since I'd expect that an Italian frame with a 27.2 seat post would be all Columbus SL and so would include the SL steerer (which has 5 spiral ridges inside the base)...BUT there were many frames that either were "tre-tubi" meaning just the 3 main tubes are SL and also many that substituted lower cost tubes such as Falck to save a few Lira in the materials cost. However, the steerer is probably the lowest cost tube in the set so the savings would be minimal, hardly worth it. BUT another angle is that this is made of Oria tubing and since there's that Treviso connection it's another strong possibility: Pinarello was a big user of Oria tubes.