Problem with white metals is they create their own coating for protection…
Clean the white metal really well with a pint thinner or at least the Pre-sol pre-cleaner.
Let it dry and don’t touuch it and then spray it with DupiColor Etching Primer, two light coats evenly sprayed but not too much.
Then you should be able to put on DupliColor Paint in any color you want.
As far as Tough Liner (is this a Bed Liner) I do not know if it is fully compatible with the Etching Primer but read up on it and see the Tough Liner requirements before using.
4x4, 5sp, Std Cab, Stepside, E4 Red
4” Lift - Coil-Overs, 6” SkyJacker Leafs - No Blocks (Mistake)
31 Spline FX4 Rear Axle, 4.56s and OX Locker, Hurst Shifter w/Optional Stick and "Made by Grev" alignment adapter