This GTAV script allows you to change your selected weapons attachments on the fly. It also comes with a hotkey that will toggle your weapons silencer on and off. Sick of your silenced pistol and you just want to blast on fools on the streets all loud-like? Hit 'O' and remove that bitch. That's keyboard 'O' as in "OH MY GOD I DON'T HAVE TO GO TO AMMUNATION ANYMORE TO CHANGE ATTACHMENTS ON MY GUNS".
This script also allows you to change your weapon tints. It also allows you to toggle the DLC skins added in GTAV Title Update 1.27 https://support.rockstargames.com/hc/en-us/articles/205705358--6-10-15-GTAV-Title-Update-1-27-Notes-PS4-Xbox-One-PS3-Xbox-360-PC-
Copy WeaponAttachmentTrainer.asi and WeaponAttachmentTrainer.ini to whatever folder your GTAV.EXE resides in.
Press 'F5' in game to toggle the trainer menu. 'O' toggles silencer. The trainer menu uses the same controls as NativeTrainer (numpad, basically).
WeaponAttachmentTrainer.ini has all that you need to change the hotkeys.
The .ini file also lets your silencer toggle setting persist across game sessions.
It probably requires some MSVC++ runtime library something or other to run. I don't know. If you can run NativeTrainer fine, you should be able to run this.
It'll probably compile on your rig with VS 2013. Probably. Everything needed to compile should be included. No need to download the Script Hook V SDK.
Alexander Blade for Script Hook http://www.dev-c.com/gtav/scripthookv/
DaBOSS54320 on GTAForums for the weapon attachment hashes http://gtaforums.com/topic/807165-weapon-component-hashes/