Thanks! I thought it used to be flush against the fender. I tried laying down and looking up underneath (I don't have a lift) and couldn't tell.I have my stock fender in the spare room so I looked at it, the back of that plug has a screw attached and it's used for holding a wire harness hold down (at least on my 2014). The plug should be flush against the fender. Here's 2 pictures of the inside of it.
View attachment 15766
View attachment 15767