Well, Valve thinks so, they just released updates to Portal, Half-Life 2, Half-Life 2:

Episode One and Half-Life 2: Episode Two have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

• Changes to take advantage of upcoming Mac graphics driver update
• Fixed door getting stuck as metro-cop behind it opened it in d1_trainstation_01

I think there’s a fairly obvious conclusion to this….