Here is what I did to fill the holes in the tailgate.
1) a vent cover I found on Ebay $35 + shipping The vent cover came bare steel so I did A plasti dip on it looks good. But you can buy one at this link I am posting.
Jeep JK Tailgate Protection | JK Tailgate Armor | JK Tramp Stamp | Poison Spyder Customs
2) For the large hole where the third brake light runs out I took one of the door plugs from my stock doors I took off. It fills the hole tight and no water gets in the hole.
3) You will have two more holes to fill where the tire bumpers were at this was a hard one. So I went to the parts store and did some looking around. I found two Toyota PVC valves that fit good and two plastic caps to fill the hole in them. They stick out about a quarter inch but it is a clean look.
total cost in the job around $50
Please all let me know how you feel about this post and I will post more tricks like this as I mod the jeep. The pics should walk you threw what I did.