Hello guys, i am really thinking to buy one of my grail watches,a cartier tank stepped .Finally one pop up and i am really thinking it . I did some research , It is manual wind , a nice oversized tank 28x38, the crown it seems correct , the dial seems correct, band and buckle aftermarket, i dont have movement pictures. One of my concern is that the back of the watch has a shine finish instead of brushed as the online examples,is that a problem ? . It is genuine ?Thank you very much in advance!!