would it damage my guitar if i used a 80cw grit size sandpaper to remove the color on THIS ?

sorry but i dont have that much knowledge in these stuff,i just play the damn guitar ,and i have just succesfully de-assembled the guitar !!
Not at all. As long as you get through the finish, paint, and primer, it's fine. Don't forget to refinish it properly.
An Airbag Saved My Dub
If that's a poly finish all you really need to do is scuff sand the surface or take the clear off of it. The body looks like it's in good condition, so you can use the color as your basecoat. Sanding thru the clear, color and primer to the sealer is un-needed.
'Aim at perfection in everything, though in most things it is unattainable. However, they who aim at it, and persevere, will come much nearer to it than those whose despondency and laziness make them give it up as unattainable.'