You are quite welcome, Rio.
It seems I will have to add about five more years...
Prof Marvel
One could probably guess those newer codes based on the previous list, although it is not totally consistent.
(There is an AE and a CE, but no BE).
Many lustra ago when I was in QC at Texas Instruments, the build revision letters were marked on each circuit board. They would not use I, O, Q, S, X, or Z since some of those could be mistaken for something else. The mnemonic I came up with to remember those letters was Indians On Quaaludes Seem Xtra Zany.