A3 2.0t timing belt

I’m hitting my head on a rock here guys.
I purchase June '13 a 2006 a3 2.0t FSI BPY.
The previous owner informed the lot I bought it from that timing belt was serviced, as all tsb on this cAr was done. So I was informed by the lot that the car was serviced: obviously I took that with a grain of salt…

Car has now 139k on the clock and I purchased with 108k.

How to know if the belt was indeed changed?

All tsb checks at audi records but no record of the belt being done. I popped the plastic cap and I see 3 things and wonder:


1-) The belt is still textured on the inside, is that an indicator of a new or old belt?

2-) is it normal to be that dusty in there? I do drive some dirt roads from time to time but that much dirty?

3-) there is a hand made white mark on the mark of the pulley. (The one to align with OT) Does that means the belt was services? Does the car get out the factory with a mark on that pulley when they are timing it at the factory?

Car runs fine i am just worried if this 2 things (texture and white mark) doesn’t necessarily means the belt was serviced and I’m actually running overtime on this timing belt.

Thanks for the reply guys.