Installation:

1: Install this mod:
https://www.gta5-mods.com/vehicles/sandkingxxxl-add-on

2: Using OpenIV, locate and access the "sandkingxxxl.ytd" file and replace the "sandkingxl_sign_1" texture with the one provided.
N.B. You will need to use Edit mode for this.

Credit for SandkingXXXL goes to legionarius