Charlie at Bogner told me that the 20th anniv would be an option, similar in nature to how the classic is an option. I don't know what this means in the context of the post above stating that one could order both the classic and anniv mods..I don't see how that could be completely accurate, perhaps partially true.
The list price of the option would be a $725 up charge over the price of a 101B
The option includes new filter caps which are somewhat similar to the classic (open, less compressed), 6L6, and some mustard caps in the signal path
The option will possibly be offered beyond 2009, dependent on whether there is on-going demand for it.
That's about what I learned during my phone call.