As Matythecrow mentioned, these seem to be gray for me as well. I've used the texture paths provided as well..
Looks like the paths provided were not accurate. Using Reteras Model Studio, I found that they are the following:
For All Ironforge Buildings: Doodads\LordaeronSummer\Structures\Ironforge\
For Regular (Snow): Doodads\LordaeronWinter\Structures\Ironforge\
Model pack looks great. Useful and modular, so you can construct "WoW Style" Dun's. 10/10.