That is the joke. There is no numbering system. We all got #101 of 1500. Asmus did the same thing apparently on their Elrond figure. Have no idea why.
That said, there's no way there will ever be 1500 of these Twilight Witchkings made. Asmus will be lucky to sell 400-500, maybe fewer... so they will be very limited one day.
Ha I must have been so excited to get Elrond I totally missed that they had numbered him. I did think 1500 of the twilight king was a very large run for him. Oh well, I still like the look of thing even if it is not accurate.