Geoff,
Thank you for your response. Yes, I have been able to remove the two long "action" screws with no problem, presumably since they have already been removed a time or two to access the reed pan and action, etc. I assume that the short screws have never been removed, since there was never a need, thus they are rusted and stuck. I definitely appreciate the tip about the penetrating oil and will give it a try. If that doesn't work, then I will have to try David's idea.