Miss Fortune's guns don't match

Recently I noticed, that on several of Miss Fortune's skins (specifically all skins released before Star Guardian) the weapons in her splash do not match with the weapons on her ingame model.

These range from smaller things like the guns being much bigger and having a differently shaped handle, to pretty noticeable ones like with Cowgirl and Waterloo, where the barrels of the guns look nothing like in the splash.

This is especially confusing considering the updated splash arts on her older skins where made plenty of time after the rework.

Now I'm not saying the guns in the splasharts should be adjusted, because honestly look pretty good. I'm just confused why there's a difference in the first place? What was the reason that Miss Fortune's guns had to be this big on her models to the point where they look more like rifles than pistols.

It's not a huge deal to me, although I think she would look better with the guns sized downs, and handles made to look less elongated.