Olympus OM-1 + OM-10 | Single lens reflex camera (SLR)

After a six-month break, I've resumed selling my late father's photography collection since October 2025. He was an avid amateur photographer for 65 years and in recent years also experimented with alternative lenses on digital cameras. He took the lenses apart as needed for cleaning or repair. I'm a novice in photography myself, so I'm describing the lot in as much detail as possible, including as many detailed photos as possible.
READ the information below and carefully examine the attached photos to avoid any misunderstandings.

OM-1 only tested for clicking and flushing, no battery tested for the light meter.
Could not test OM-10 due to no battery.
Both devices look well-used and could use some love when it comes to cleaning.
Perhaps both still need fixing?

Photos are associated with the description.

Please note that shipping can be combined if items are won in the same auction. This is to save costs, now added to my advertisements.