A camera of that vintage is likely to also have other issues. Need for foam replacement is common. An overall CLA is probably warranted. Contact these folks, Olympus specialists http://www.zuiko.com/

Also to be considered is dealing with the OM-2 need for mercury oxide constant voltage cells. There is the Wein air cell, but these expire once activated, even without camera use! Alternative are adapters that use today's button cells and a voltage regulator circuit to provide the constant 1.35v needed by the OM-2, and some places can do an internal mod to the camera rather than always using an adapter unit. Again, ask zuiko.com about what they recommend.