Any chance anybody could make me a clean portal gun?
Since there's a great tutorial already written by Sicklebrick, I'd suggest you to follow it up. Check here
There's still another option; you can mess up with your .vpk file editting it and changing the path where it looks for the portalgun textures. That explain here
If you prefer to use the coop portalgun textures, you must know that both are available into a special packed file called pak01_dir.vpk located into your folder portal 2/portal2/. These special .vpk files can be opened to access their content with GCFScape. Once you download it and install it, you can open this kind of files and you'll see a tree structure of folders. I'm not at my computer at the moment, so I can't tell you exactly their location inside those folders... they must be under the materials folder. The single player portalgun textures are locateed into the folder materials/models/weapons/v_models/v_portalgun (here it's the first person gun you see when you're playing) and materials/models/weapons/w_models (this is the model of that little gun that you see when you are watching yourself through portals)
I hope that helps!

I've changed my viewmodel position with the console commands so it's a bit different, but I like it.
The only problem is that the normal maps still make it look like it's dirty, and I can't seem to find how to edit that.
viewmodel_offset_y #
I use 10, but it shows the textureless part of the model when I circle jump/ turn quickly. You can use other values to left handed or hold it above your head as well.