Some of my Wargs. These serve me both in my Isengard and Dol Guldur / Mordor armies.
The models had an option of leaving out a small piece of plastic just behind the neck which would reveal a small hole in the back of the model. The Warg Riders had a matching peg on the bottom of their saddle that would fit into this. Since I use these as both Wild Wargs and as mounts for Warg Riders, I elected to glue the full Warg together and paint it, while also cutting & filing the mount peg off the riders. I can now use just a small piece of Blue Tak when I want to hold a Rider on. This also makes it easy to handle situations where the Rider is killed and the Warg survives its Courage Test to stay in the game.
On a side note...I never understood why Games Workshop's official painting guide used grey faces for these things, but I went with what I hope would be a more realistic color scheme.