A question for the experts. I just got my relatively new to me ‘70 Speedmaster back from service and was admiring it in great detail when I noticed it has a B2 crown rather than the A2 MWO says it ought to have. I also noticed that the B2 is correct for ‘70’s models, again according to MWO.

Maybe I missed it, but why can’t I find a reference in MWO that shows the use of a B2 crown?