I have two HP-85 computers that were installed in a piece of government data-logging equipment. Consequently, they are very nice condition.
The odd thing is that they are both marked HP-85 rather than 85B. They are, in fact, fully B equipped. Mass Storage ROM built-in, 32K RAM, Electronic Disc, etc.
Inside the printer compartment of both it says,
"82972A Upgrade Installed."
I can find nothing on this "82972A upgrade." Could this be an "A" to "B" upgrade? It doesn't make sense that they would just put an "A" case on a "B" so I'm guessing that this is some sort of upgrade from A to B.