There are several places that make legit Disney pins. You may have pins from Germany or Spain. These look and feel different. You might want to search for your pins on pinpics.com and see what info comes up. Also you might want to ask at dizpins.com on the message boards.
The clearance outlets (I think there are 3) sometimes have some pins. 2 outlets are at the Belz outlet center. Not sure location of the other. Sorry I can't give driving directions.
I don't have kids, so I can't comment on the way CMs trade with kids, but typically if it is stamped Disney it is accepted. If you aren't sure, you can always ask the CM. As an adult, I've not noticed too many of them checking the backs, but they are probably trained to know the pins. The only ones I've had them look closely at were pins from the foreign parks--and that was just to say "Cool, I have'nt seen this one before."
Good luck. Hope all works out well for you and the kids.