DJM is there interest in something like this?
if so, what type of arms and gun would u like to have?
There is one way to find out: offer what you've got and watch the numbers of downloads.
Offering assets, paid or free, is a potential way to get some money in the long run, when you finally got a wide range of stuff most people are likely to need, having some Godot-ready-fully-tested 3D assets, with potentially a little test project with all properties set, may help you to get this (niche ?) market I guess.