We sold these pedals in the late 1970s and they were indeed very smooth and beautifully finished. They were also priced up there with the other top pedals of the era, Campag 1037A, TA and Phil CHP sealed bearing.
The cages were replaceable which was a good thing as the use with shoe cleats of the day had a tendency to bend the plates in. They only were produced for a few years, fading well before Look clipless knocked out almost all traditional pedals. I always wondered how Barelli came to be the name for a British product.. Whether it was someone's name or an attempt to sound fashionably Italian?
Dale Brown