Update: As I suspected, the server only looks like it allows a query about what codes the user has already redeemed. Sadly this still doesn't explain anything about Bungie's bizarre numbering system. (Grrr, fine spell-check, I'll add "Bungie" to your dictionary!)

My personal experience with web coding is relatively small, and at any rate the code list is static and any changes I make to it wouldn't cause it to bring up any additional information as that information is not stored on the client's end. I'll try to do some poking around though, and see If I can get any additional information. Thanks for your post!