Hey, I have a Marshall JCM 900 HI Gain Dual Reverb and I want to find out the date it was made, I dont really have any reason just for funs sake but i cant understand how it works. All sites I've visited has said that it should be a sticker with a barcode but i cant find any, all I find is what I think is the serial number, the numbers are "Y41720" so if anyone know what that says or have any tips on where to find the real serial number if that isn't please let know thanks! P.s my cameras broke so I cant post any pictures but if you really need I can solve it!