It would probably better if this actually was a bug but I thought this was intended behavior of whatever system is at play for giving weapons skins. It’s consistent across the board for every type of weapon that has multiple variants with visual differences.
I think this is intended because the cosmetic skin description says “applies to…” and lists the different types and Kantrael in the shop. It was the same for one of the autogun skins and a ripper gun skin as well I think.
Ah but the skin that comes with the imperial edition do not modify the model like the other cosmetic and just apply the paint job to the gun so after all that may not be working as intended.