Originally Posted by Andy_K

I don't know the answer, but I'm curious to hear opinions. My 1974 Masi has top tube cable guides, but it has been repainted and has several braze-ons that it shouldn't, so I don't think it's a reliable data point. I think someone mentioned recently that the California shop sometimes made semi-custom builds with irregularities like this. I have no idea when they became the default.

Are you wondering about the Italian Masis or US?

The registry at Bob Hovey's site (Masi Registry USA) lists quite a few bikes with top tube guides in 1974 and 1975.