If you just got the grills by themselves headlights alone won't really work .
You will need the appropriate headlight buckets and retaining rings for it to be fastened correctly .
And besides you can get the sealed halogen 7" lights at any auto parts store for less than 10 bucks each .
Or opt for the Euro lights at around $90 for the pair .

I do have a complete 316 gril set- up for sale , comes with grills , buckets ,rings and sealed lights .