There are plenty of Icons already in the game that are only visible while hovering over the weapon in your Inventory/Shop
I have extracted all those Icons from the game:
I thought that it'd be a nice touch to display these on the Weapons themselfes,
although its probably best only to do that in the shop and maybe your inventory but not your weapon slots in half-time and the Lobby
I have already prepared a sample of how it could look.
I also recommend lowering the actual image of the weapons (and thier names) slightly.
(I only lowered the BSG and RL a little as they were partially behind the icons in this image)
Some Icons may need a slight rework to make them more uniform with each other (i.e. Melee, Turret and Spreadshot are all fairly diffrent from one another)
I think this could clarify a few things for new players browsing through the shop, wondering what weapon they should buy, and give them a rough idea of what a certain weapon does,
since not everyone actually reads the details or pays attetion to those icons as it is right now.