Do you have a manual attenuator or the electronically switched one?
There are 4 screws on each end of the attenuator, if you have SMA/3.5mm connectors, then remove the nuts on those connectors, the cover plate between the connectors, and that will expose the 12-16 screws that hold the top cover with the attenuator pads on it. You will need to loosen at least one end plate to take the
top cover plate/attenuator plate off.
A lot of this information is in the HP/Agilent/Keysight Microwave Accessory catalog and in the HP 8495B Operating and Service manual, yes it does contain theory of operation, schematics, parts breakdown, and parts listing. A .pdf of the manual is attached.
Don Bitters
