Oh... Duh! & Double Duh!
The precious owner said he could not get the back open. I had skimmed the online manual, and decided to take the risk.
Nothing looked broken. The latch seemed to want to release. Read the manual closer, doing everything the manual said...
Then the "Duh!" Moment... The eye cup was on the camera. The base is extra long to act as a cover during long exposures. Slid the eye cup off, and she opened like she was built this morning.
Insides are nice and clean, and the seals are in pretty good shape.
Thanks for the help!