I have picked up BOX CAR #159000 NYC MARKINGS X6454 BROWN IN COLOR . I LOOKED AT THE BOOK ON IT AND IT SAYS IT WAS BUILT IN 1948 BUT THE MARKINGS ON THE CAR SAY NEW 9-44 IS THIS COMMEN OR A MIS PRINT.
I originally thought the same until I was enlightened by one of the forums. The dates on the cars do not always reflect the actual date of manufacture of the model. Some dates are reflective of the prototype car used as the basis for the model and/or the first date the item was catalogued.