Hudson308 

While scouring Craigslist and feeBay for vintage Brooks for a couple projects of mine, it became apparent that the majority of Brooks B15 & B17 saddles I asked about had no date stamp at all. When they did, it was usually (but not always) a B followed by two numbers stamped on the rear of the bottom frame, near one of the curved ends. In a couple instances it was closer to the center of the rear frame. A number of experienced sellers were surprised to find the stamp when I told them to look in this location, as they were stamped pretty lightly. I've assumed the two numbers were the last two digits of the year of manufacture.The stamps seemed to get more common toward the end of the 70's. I've got a couple saddles that the provenance is fairly certain from the early 70's, with no date stamp at all.