I have a Golden Australium Gun Mettle coin. Now since the Halloween update the ugly statue is next to my name. Halloween is over now so I want to change it and show my Australium Coin because I think that it looks better. But I can't find a way to change it back. I tried deleting the statue but didn't change anything.
As far as I know, this isn't possible. The icons relating to items like the Gargoyle or Update Coins have all remained static and seem to relate to whatever campaign was on last.
There's no way of changing the icon as far as I know.
TF2 doesn't currently support this.
There are some references in the game binary to selecting a campaign medal, but there is currently no GUI or command to actually select the campaign medal to display.