Originally Posted by
verktyg
...I have several with the number imprinted in the underside of the leather in 3/4" numbers.
I don't think those letter (not number) stamps are date codes. The best I've been able to find about them is stated here:
Date of Manufacture of Bicycle Components can be used to date a bike: component dating
The earlier stampings on the underside of the leather were simply 'batch codes', for quality and stock control purposes, and would have been well understood by the workforce at the time, although they were almost certainly never recorded...
I have several '70s vintage Brooks B15 saddles with these stamps and so far there is no discernable rhyme or reason. If you have the decoder for these, please let us know! Here is an example from the early '70s I'd love to see decoded:
