How to test if my Cisco QOS configured on my router works

Hi All,

I have a Cisco 2801 router at my home configured to work with QOS.
I can see hits on the QOS ACL so I can tell that I configured it correctly.

My questions are:
1. How can I verify that packets marked with QOS are leaving my router BEFORE packets that do not match my QOS policy.
2. Can QOS be done on one device or should I need to have at least two devices?

TIA