Hello, I now have this frame. I bought it as a 1952 Colnago but I am convinced that it might be by another frame builder. The rear dropouts have 19 serrations/teeth so presumably it was for the Paris-Roubais changing system. The cast fork crown is not [in my opinion] a Colnago pattern and in any event, it is nickel-plated under the flaking repaint job. It is definitely not chrome. The frame's front lugs are also polished nickel-plated, again beneath the repaint job. The frame serial number, on the seat tube /top tube lug, is 110.09 contained within a rectangular engraved panel. 09 is also present on the underside of the fork crown. On the underside of the bottom bracket is a large "cheese-headed" screw and there is a spring-loaded oiler on the top of the bottom bracket. If anyone is interested I will take photographs and send to their email address. Mine is keithdale@live.co.uk. Please don't ask me to put photographs on here, because quite simply I haven't a clue as to how do it, despite someone earlier explaining how to. I'm totally hopeless at computer/electronic "things" !
The head tube decal refers to the Rome and Mexico Olympics, so the purple metallic repaint job was done after 1968 and there's no sign of a Colnago cloverleaf motif. A mystery to me.