It might be. Just because WC3 uses the footman model does not mean Blizzard necessarily made it (they might just have a good licence over it). A lot of graphic content in budget (WC3?) and AAA games is generic "off the shelf" nowadays. This can be anything for generic models you hardly ever notice (foliage, stones, etc) to surface textures that come from standard libraries (do you honestly think people mess around with values to make a rock look like a rock?).
In any case if you can get the link to the advert (proof) you can probably post it on their forums and hopefully some blue would comment. Alternatively they might have just written WC3 off for now (abandon ware?) so anyone can use the assets and not be prosecuted as Blizzard cannot be bothered to enforce their licence rights. This certainly would explain the stupidly high abundance of pirates playing the game now (for the love of all that is good and honest, if you like the game and spend >100 hours playing it please try and buy it).
