As I wrote at Collectors' Quest, we've a large lot of original (and very retro) GPK cards.
We offer some cards still in the packages, as well as single cards -- and we are very happy to hear your offers on multiple purchases. Just E-Mail WHYC and let us know what cards you are interested in & your offer.
Cards in packages, from the 3rd series, appear to be the first printing of the 3rd series, based on the wrapper code; again, I refer you to the CQ article for more information on this.
Even though I’ve an opened pack from the first printing, I cannot verify for certain that all of the 28 remaining wrappers contain cards from the first printing. Or, in fact, that these wrappers were never opened and resealed. But the odds are in the collector's favor.
Single cards are all in very nice conditions. We hate grading systems (because even when well-defined, they are subjective), but we'll go out on a limb and call them Excellent/Mint.
If you'd just like to enjoy the GPK memories, see scans of all the cards at Collectors' Quest. (And if you collect them -- or anything else -- why not upload your own collection to the community? It's free and fun!)