Wow. What a great find on your Carrera brakes. I have them on several of my bikes. The finish is nice, and the stopping power is more than adequate. As for the time frame, I'm not sure. The first set I had, I put on a Peugeot PX 10 that was subsequently stolen in 1980. The two sets I have now differ from one another by one having more black plastic parts than the other i.e.: plastic vs. chrome dome nuts, and metal vs. plastic quick release cams. I think they stop better than Campagnolo NR. ( blasphemy) and are more appropriate to non Campagnolo equipped European bikes.
Chris Van Scoyk