Just like JT said, in the olden days they used to test Macs and fix them before sending them out -- they probably do today too, but they would not fix it like this today, if for no other reason than most of the Macs that are shipped today are too small. (Also, timing issues probably caused by external wire fixes like this would throw a modern machine at >1GHz totally out of whack.)
But, although I haven't seen it on very many other machines, this isn't the first time Iv'e seen photos of an LC III done up like that.