Far Cry 5 - Locked and Loaded Trophy Guide / Achievement Guide - Fully customize your weapon (Campaign only) [Bronze]

A very easy trophy -- go to any shop and buy the two sights for the bow -- trophy unlocked! It costs $1695 total (Red Dot Sight = $795, Marksman Sight = $900). That's all the customization options for the bow.
You do not need to buy any skins/colors, just the two sights.
It's cheaper than upgrading firearms. If you do it with a firearm you must buy every possible upgrade except skins (sights, silencers, extended mag).

The bow is found in many places and from many enemies over the course of the game. After you've found it, it will become available for customization at every shop.