I really love the new Kan models, I might just have to build a Kan wall army.
Regarding this one, I like it! I wouldn't do more than two of a multi-squad group modeled like this since the
CCW arm is pretty static, but I can definitely see a Grot mimicking Shoota Boyz who hold their guns like that and it adds a nice variety to poses.
I may even be tempted to model one with a crushed barrel as if the grot wasn't too careful with pressure control while steadying his gun. If you had extra bitz you could model a second gun on its shoulder as if the Mekboy just grafted another one to it rather than replacing the arm entirely.