I mean Valve has used the naming format "Episode One" and "Episode Two", my guess is they will have the subtitle "Episode Three" rather then what is currently displayed for this game right now "Episode 3".

We should probably just wait to see what they refer to it as (i.e. box-art/gameplay), before it gets changed. Unless they have referred to it as "Three" already.

It's true the other episodic games are named as 'one' and 'two' on Giantbomb so it makes sense for this to be known as 'three'

Makes sense to me.

This was initially named Half-Life 2: Episode Three but someone seems to have changed it.

blasphemy!