A货 vs. 原单 (yuándān): This is a key nuance.
原单 (yuándān), or “original factory order,” refers to products supposedly made in the same factory as the genuine goods, often sold as production overruns or items with tiny defects. They are technically “grey market” goods, not fakes. However, dishonest sellers will often label their best A货 as 原单 to command a higher price. True 原单 items are very rare.