I once had a CAA Engineer pop up to do a survey on an aircraft that was due to receive a new CofA, having been grounded for 7 years.
He spent ages going through the logbooks all the way back to 1940, when it was built at Cowley, Oxford. We then went out to the hangar and he spent some time ensuring that serial numbers and placards were correct. After about 40 minutes, he declared himself satisfied and as we were leaving he turned to me and said, "You know I always remember Tiger Moths as being higher than yours!"
I tried really hard to contain my laughter. In order to get the a/c into the hangar, I'd removed the main wheels and the stub axles were sitting on two "skates". The Tiger was about 10" lower than with the wheels on.
Obviously a thorough inspection as he did not appreciate that the camouflaged and yellow Tiger had no main wheels.
People only inspect the things that they are looking at - it is not unreasonable to assume that the rib-stitching could have been incorrect for many years.