Well,yes Kellerher Auctions is right. At least in the way that every hand-cancelled item is unique. But that does not mean such items a valuable !
I believe the describer mentioned the combination and route in which the item travelled was unique for the time. Not typical.
This interesting and unusual piece is now available for auction at Kelleher auctions item number is 6011 its on Michael Rogers online on kelleher Auctions website.
Congrats, I hope you make some money off it, I see the suggested price is two hundred and its already selling for one hundred dollars. Good Luck