I'm most interested in finding out exactly what the letter codes mean on the cantle plate of older
Brooks saddles (if that's even knowable at this point). I've always gone by the information found here:

http://www.vintage-trek.com/component_dates.htm

Unfortunately, that indicates that the meaning of the letter codes is lost to the ages.
Is that true? Regardless, it would be nice to have that kind of information about date
codes on the Brooks site so collectors like me can easily find it.