Help identifying a part

[Kajunxplorn]

I purchased a used 2015 4rnr with a GOBI rack installed on it a few years ago. Today, I went to install the OEM roof rails and within the bag of bolts were 4 plastic parts that I can't figure out where there go. I checked numerous roof rails videos and pictures and didn't come across them. The pieces are two sets that are symmetrical to each other.

Any help is appreciated.

 

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Thise look to be the inside caps. So rear of the bigger end caps.. those go under the rail and snap into place towards the end cap