Gentle Giant teased the possibility of customizing the statue purchasing experience. The Thanos at SDCC15 was used as an example for their new color capable 3D printing. In the video below, towards the end, he discusses the possibility of GG offering multiple changeouts/ hand positions you can customize your order with.
Of course, like he states in the video, this is just their goals and the direction they might choose to go. Nothing is certain.
http://youtu.be/ZJAKDCUaMTg