Welcome to the forum!
Here is a link to a schematic that shows the stock mounting parts.
Yamaha Motorcycle Parts 2009 TW200 - TW200Y FUEL TANK Diagram
The rubber damper pucks (Item #4) just push onto posts on the frame. You may still have some of the rear mounting hardware (Items # 5-10). If not, someone here may be able to help you out.
Hope this helps,