Nose cones (plastic behind the headlights) come in either chromed plastic or black plastic.
The simulated chrome Nose Cone would be typical of those used on the model 500 Diablo. Note that original 500 Diablo chrome nose cone would be black in the middle. I no longer have these chrome nose cones available. The black plastic nose cone with the red around the perimeter would be typical of those used on the 502 & 503 Diablos. You can use this same black nose cone on the 500 models and paint the perimeter silver.
All nose cones come without holes. For the 500 and 502 Diablo with the flat mounting style headlights, you just drill holes to mount the headlights. The 503 Diablo uses a bucket style headlight and so the nose cone needs to be cut out as shown above. I’ve found the best tool for this is a Dremel Tool with a drywall cutting bit on it. Just hold the nose cone in place and cut around the rectangle opening of the brace within the hood. Once cut, the perimeter of the nose cone can be painted red to match your Diablo.
On all three models, the headlight mounting holds the nose cones onto the hoods.