If you gift it I would think the person would get one copy and have three in their inventory.

If you're referring to that Natural Selection II 4-Pack Giftable Copies it's only one copy that came from a 4-pack.

When you buy a four-pack, you will automatically get one of the copies of the game put into your library. The extra three copies are added into your inventory, to give to your friends or other random people on Steam. You should be aware, though, that you cannot buy a 4-pack if you already have the game in your library, because of the aforementioned "adding one copy into your library" thing.

if you have a 4-pack in your inventory, i think whoever unpacks it gets one in their library and 3 more copies of the game in their inventory

Sometimes Steam allows purchasing 4-packs as giftable copies. It's rare but it happens. The inventory item description should clearly state that it's a "Four pack" in that case. It acts as a normal 4-pack when activated, though - so if you gift that 4-pack to someone and they activate it, they will get 1 game in their library and 3 giftable copies of the game in inventory.

the same way as 6packs, except there's just four of them

For all unbelievers out there here is a screenshot buying a 4-pack as gift is possible