I know maybe I sound stupid asking this, but do you remember who you bought it from?
At least his ethnic group? Since he said he could always get more, maybe he bought it from some speciality shops? I mean if he is Chinese for example, he could had bought that off chinese store which mean it could be made in China.
Its a long shot I know, but maybe knowing its origin could help.
It's worse than a long shot. You'd have a hard time finding someone more Caucasian than me, yet I have some Asian-origin decks that are considered pretty rare in Asia, not to mention the rest of the world! On top of that, I live in New York - a city where if it didn't come from here, it probably had to come through here for approval first! (In other words, there are few things that are unattainable in New York, except perhaps cheap housing...)
I don't think that one's ethnic group has much to do with what decks they have access to, especially considering how global the economy is these days. One doesn't need to be Chinese to have rare Chinese decks - one could be Filipino, Japanese, Caucasian, European, African, whatever.
You were on the right track with your NEXT question, though - jokers, ad cards, the Ace of Spades. Do you have any of the more unique cards of the design, the ones that tend to reveal brand, manufacturer, etc. Perhaps there's a tax stamp - I think it's the Ace of Hearts for Argentinian-sold decks and the Four of Clubs for Spanish-sold decks that have a tax mark or a maker's mark on them, much like the Ace of Spades in most International Standard decks.