After reading my new edition for the 69 Z/28, I checked what I believed to be my original radiator (well at least I believed that the tanks were original, as I had it recored probably about 1983). It does not have the original tag that I always thought was needed to verify it as original, but after reading the book I discovered that both right and left tanks were embossed with codes as well. Sure enough both my tanks are embossed as the Jerry's book states, "CB" and "IH" I believe. When it need to be recored again, I just bought a repro instead, but kept the original. Another part I'm glad I didn't throw away!!