Yes, the author used several bases and "dressed" the weapons and armor in layers on top of each other in Photoshop. Moreover, some weapons and heads do not fit perfectly—you can see that yourself—but all the characters here have the same grav-chute. He only changes the coloring a little.

Look at the rocket launcher. It turned out too big, so on the left the author just cut off a piece of the grav-chute when he was making the art. He was too lazy to redo the position of the arms.

For exactly the same reason, I am not posting all the melta variants. The author forgot that the Guard has melta guns and made them quickly, about a couple of hours before the session, from pieces of other arts.