In FNaF, the most mysterious group of animatronics in the franchise have undoubtedly been the original gang from the first Fazbear's restaurant. Who most of the community has imagined as a repaired form of the withered ones seen in the second game... however, what if that was never the case? Well in this extended theory I will convince you that in fact they always looked like the "classics" seen in FNaF 1 and what all that implies in the Lore.

Edited reference image (by me):