I own one of these. Really nice scanner.
For those who may worry, cleaning the inner glass surface is not difficult on this model. In picture #3 above, notice the small circular round covers with what looks like a flattened 'V' in them, two at the bottom and two more at the top of the dark bezel surrounding the glass.
After removing the lid (lifts right out, no tools required), remove those circular covers by applying some duct tape, then lifting straight up. Under the covers are four screws. Remove those screws and the bezel with attached glass lifts right out for cleaning.
The accumulation of haze is an outgassing issue that is normal in these units and may be periodically wiped clean. Mine is due for another touch-up right now.
Best of luck with this sale.
Ken