Continued with inspection panels for empennage. Wanted to use nut plates and screws from the spoiler access panels. Removed nut plates to discover that the rivets for the original nut plates are something slightly smaller than our today's standard 3/32 AN rivets. 3/32 rivets wouldn't fit in the holes on those nut plates. Looked at the screws holding the cover plates on and found that the closest screw to them is a 5-40 screw. Yes, a #5. An M3 is close but the 5-40 is even closer. So, some soul searching here and the reality is that I'm going to have to make some changes to the aircraft to make it reasonable to rebuild and to maintain. So, after some work cleaning up those original nut plates, I'm using brand new nut plates and 6-32 screws to hold the covers on.