Al, I had just the opposite problem. The first time I tried to remove the saddle, the screws were so tight for the full length of the threads that I thought they might shear before I got them out. I checked the screws with a die and those threads were good. Then I checked the holes with a tap and it wouldn't go in, so I cleaned up those threads with the tap. All is OK now. You might have to drill and tap for the next size larger screw on that side, or install a threaded insert.
1952, first bike a Simplex Servi-Cycle cruiser style. 62 years of other types, now back to a cruiser style XR.