I recently picked up what looks to be an early 70's Bottecchia frame which came with this headset. I'm thinking it could be a Bottecchia unit except it doesn't have their name cast in as I've seen on other Botty headsets. It's also the only one I've seen with the toothed adjuster washer and that was made to be hand tightened. I've seen pictures however of a Bottecchia lower head tube that had what looks like this same lower headset in it... but no shots of the upper set were available. If it helps, there are 3 pin wrench slots cut in the top nut, and it takes a pretty standard pair of caged bearings.

Any help appreciated, thanks,