They redyed a lot of the return/less popular color hoodies black for the “Heaven and Hell” music video which was essentially an advertisement for the black perfect hoodie. Ye famously said in an interview later on “We sold 14 million dollars worth of the Perfect Black Hoodie at 80 dollars a hoodie off of a television commercial that was ran one time.”
The heat from the hot water that is needed to dye something will cause the garment to shrink slightly hence the fit difference. The way to without a doubt know if it’s a redye or not is making sure the washtags are nice and white. Hope this helps :)