I checked on Zetecinside.com and it seems that the dimensions for those 16v badges (The ones int he first post I made) will most likely cover that 5/8 inch hole:
Dimensions: 2.5" x 0.8" (65mm x 20mm)
0.8 inches height will have no problem with that, and the 2.5" width will definitely have no problem covering that hole!