Yes they are.
But uness you can flash another CC# into it, you can't add money to it, that info does not reside on the stripe. Doing this pretty dumb, since the number embossed on the card will not match (not that anyone checks this).
Each stripe has an ATR (the card's way of saying hello to the reader) and your account number and the issuing banks FedWire transfer #s.
It is relatively easy to flash new data to the card, but you'd need to get valid CC#s and FedWire #s to make it work. Each bank has a different FedWire # and each card company has a different ATR.