I did some homework and came up with these skins as well.
Kar98
Here's one with a full red dot scope.
http://www.fpsbanana.com/skins/11928
Here's one with a 'floating dot'. Basically a red dot, minus the plastic casing.
http://www.fpsbanana.com/skins/29909
M1 Garand
This one has a few variants on the actual red dot of the scope, but I figured it would suffice.
You'll need this file first.
http://www.fpsbanana.com/skins/47561
I would imagine that you would go through the same process of putting them in place of the other textures or what not.
Enjoy eGO.
Those are the basic skins yes,but the post says customized, because I did quite a bit of work with the glass texture for both skins. With the original files, the red point was slightly off center. "No big deal" you say, wrong. With the fixed glass texture, its right on the money... BOOM HEADSHOT!