Unreleased 2012 Turtle Prototypes?

[Crognard The Barbarian]

Upon looking at stock photos of the RC Patrol Buggies, I noticed that the head sculpts on the turtle figures riding the vehicles are different than those that are available. They appear to be attached to the Battle Shell bodies.

Has anyone else noticed this? Does anyone have any information on this? I personally like those sculpts and would like to add them to my collection.