I don't know if anyone sells them.
As far as their purpose, I was thinking you could stick a screwdriver in there and adjust the tension on the vent wing or something like that. Don't hold me to that, though, as I really can't remember. I was going to look at one of my parts cars but I didn't have time to check it out. If that's the purpose your Charger wouldn't have them since it doesn't have vent glasses.
Dallas