Dark Interval is getting its own MP5k model. Though the biggest part of the work — creating the textures — is still ahead, and I think that the fire mode switch should be a separate model so it'd possible to control its position in the code. Or whatever.
I also cannot into model animation, so I think that would be the one of an SMG1… or the Leak old SMG.
I think the best way to get the mesh textured would be to get its uv layed out then bake it in
xnormal - free program for AO baking and normal map creation
Then use base colors to do the general texturing. Then continue adding detail to it then adding the bake as a overlay to the current texture work giving it a nice look.