Riser block installation question..., drilled holes in the spoiler? Options

[AMCMoe]

Ok it seems I'm the only one having this problem...

Where the risers bolt onto the spoiler, does anyone already have the holes predrilled and have the metal threading in there? My spoiler only has the holes where it bolted to the hatch, not where the riser blocks bolt onto. So I drilled some holes in the correct place on the spoiler but I don't have a clue what to put in the hole to retain the bolt. I took some pictures, they're bad quality because its dark and I only had a camera phone.





If anyone can think of any suggestions besides going to a body shop it would be appreciated.

[AMCMoe]

Thanks for the reply batman. I'll use silicone on them as you suggested, but I can't use those screws anymore. After I drilled the holes I had the same idea of using those wood screws but it was a little late. I wish I wouldn't have drilled those holes or I would have used screws like you said. Any suggestions for the holes I drilled already?