I understand that but like I said cards have been faked too, the DSF Jessica pins and the DS Jessica jumbos all come on fake cards too you can tell because the cards don't feel the same and all the shopping pins did not come in a cellophane bag they came in a zipper bag with wrapped foam. To depend so much on a card is not so bright I could get a real card and put it with a fake pin. You can buy real cards at myDpins too and switch em out.
But, you can _tell_ they are fake, right? So that helps right there. If someone has a pin on a fake backer, you know to walk away.
If it's a completely generic backer then I don't necessarily need it (but if it's unique, I always want it, and will re-buy the pin just for the backer if I can), but I usually like my pins to include the original Disney barcode, where ever that was placed. Some of the DSF pins have the barcode on the plastic bag, and nothing on the backer (in that case, I'd want the plastic bag), other times the barcode is stuck to the backer itself... I'm a collector of TONS of things (why to many in fact), and even dating back to toys from the 50's, original packaging is always key to increased value of an item. If I see two identical pins that I really want, and one is loose and one is still on it's card/in it's bag, I will happily pay more for the bagged one knowing that I have the 'complete' pin (pin + packaging). I actually think it's kind of funny that so many people in the pin collecting don't care about the packaging! It's the complete opposite with nearly every other kind of collectible.
I don't even like that many people will take the pin-backs off the pin, and then poke the pins through the plastic bag to pin them into trade books... But I've never actually complained about that.
You just wait, someday people will start evaluating the _condition_ of the backer cards too... A crease in the corner?? Oh, that's worth less...
I don't know of any rhyme or reason to which pins have them. I don't even know if that number is the same for each identical pin, or if it's a unique number. I've never seen these numbers on a Pinpics listing. Either way, I suspect it would be far cheaper to fake that stamp than to make fake backing cards.
The numbers are some kind of SKU/tracking # used by the manufacturers (possibly also at Disney's request) that I think represent a series. When I look through all my DSF marquees, for example, they are all different and the last 5 digits are slowly increasing. But looking at all the Lady & the Tramp trains that came out last week, all of them have the same number (and actually, the Mulan ones have the same number... So I'm confused now.
). So far every PTD I've seen (the last 5 I think) has had the same number as well (but different from the other pins I mentioned)... But the nice thing is that if you have a DSF L&TT Engine pin, you know it should have a certain number on the card, though that number isn't unique to _just_ that pin...