Both are easy fixes for an experienced tech. If the screw is rusted/frozen in the post and the screw slot is destroyed it can take a bit of time to get it out. I would guess roughly 1/2 hour at whatever bench rate is charged plus a few more dollars for a replacement spring and screw. This guesstimate comes with the caveat that without seeing the instrument in person, it is difficult to estimate anything with accuracy. There may be other issues with the instrument that you are not aware of as well.
