No reason for them to make it up, just wish they would say from where. I have gotten material from NYStamps still on the seller's from where the was purchased before being sold or consigned to NYStamps. Really no different than the stamps in the ABC Sale (see:
https://goscf.com/t/85124 ) which contains material still on another company's priced old retail counter stock sheets. Stuff moves in the market still one the old pages, auction or retail.