Squeaky AC/heater 'flap'. Is this normal?

[Andy_V35Sky_350GT]

Well, winter has arrived in sunny Bris Vegas and I've been using the heater for the first time since I got my car. When I turn the heat up (normally I leave it on 18 with AC but turn AC off and put it up to around 25) you can hear the 'flap' moving to let the hot air through from the engine (I am assuming thats what it is because it used to happen in my Mitsubishi FTO and was told its just a 'common' thing with Japanese cars).

Is there anyway to lubricate it to stop the noise? Its not bad and certainly isn't too loud, but for a nice luxary vehicle you want as little noise as possible