Either for some glimmer and motes of light or a combination with planetary materials and silver to buy a design from a vendor to customize the look of a weapon. Like the Suros ARN-33, that weapon has a unique design, and all weapons should be able to have a chance at looking unique. Only the exception of exotics to stay the same as they are. A vendor would have a wheel or box that we put a coin or key or designated item to for a random weapon skin. The chroma system doesn't have to be used, yet it would still look awesome with that added to a design.