How to fix white underside of truck, and how to remove Soldier Fortune gun?

[Wave]

So a few of the trucks I have downloaded have this issue where the underside of the body of the truck is completely white.  I fixed it for one truck, and I have no idea how I did.  I tried putting the trucks into the v4 pack, but it still won't load the correct texture. If it helps, I specifically have this problem with Saigon Shaker 2016 and Xtermigator 2016 in version .4.7.  I'm just lost, so can someone guide me in the right direction?

Another question I had is is it possible at all to remove the gun from atop the Soldier Fortune gun, or would someone have to make a whole new truck?  If it's possible, can someone tell me how to do that as well?

-Wave

[monsterjam16']

For the white textures, its most likely a missing png, so try to put fiberglass.png in the zip, as for the gun, the only way to do that is do put into blender, and remove it there.