I have been converting my base for awhile now and have been looking at how the stock spoiler attaches and came across this thread:

Thread on rust (pay attention to the second image)

Besides the (2) 6mm bolts the spoiler is loosely attached with 4 plastic fasteners. The fasteners are shown here:

Picture of plastic fasteners

The fasteners are 2 pieces (from right to left)
spoiler side half, body side half, both pieces together from bottom, both pieces together from top.

Looking at the thread above it looks like the bottom half is still in the car ... is this in fact the bottom half of the fastener? how is the fastener attached to the car?

My theory is that there are (4) 8mm holes drilled into the body before painting for these fasteners. and the fasteners just push into these holes and seal with the neoprene washer.

It also looks like the 2 main 6mm bolt holes on top might just be rivnuts as well vs. welded nuts.

Can someone confirm that I am just seeing the bottom half of the fasteners still stuck into simply painted holes on the body?

If this is true, i would like to drill these 4 holes into my hatch, touch up paint around them, install 2 rivnuts for the main 6mm bolts ... and basically have the same oem attachment.