If it is ever proved that this really was the reason for the crack found on one of the -200's then you are absolutely right, they will have done the same to other a/c too; including perhaps some of BA's big a/c which I know were also Heavy maintained at FLS. Whether that ever comes to light your guess is as good as mine. Re-skinning a few 747's might just be too expensive for a sensitive subject like this coming out of the hangar.