you can pop those blobs to reveal a square hole which can be used to with a carriage bolt to hold the end cap on the bumper a bit more securely than the plastic tabs.

alistair

On Jan 12, 2014, at 11:02 AM, Eric Caron <ecaron1@COMCAST.NET> wrote:

> In the shop I looked at the end caps and realized that the one plastic blob  on each end that sticks out a bit and looks like it might hide a screw head actually doesn't.  It can just be left alone.  it does correspond to a hole in the bumper that didn't seem to have a purpose