Traveler Install Question

[folkmeister]

I am undertaking the installation of a Lewmar Ocean Series Traveler (Size 2) on my Sabre 34 MK II.

I have a question about the attachment of the traveler end stops to the track. It's clear there are two bolts on the end stop, and the intent is to drill holes in the track to receive them. Plastic inserts are provided for the holes I will drill in the track, presumably to guard against galvanic corrosion.

It doesn't seem like the holes in the track should be tapped, given the presence of the plastic insert. It also doesn't appear that they use nuts on the bolts (based on the tiny pictures that came with the end stops, which lack any sort of words or instructions!)

So - are the plastic inserts essentially like glorified drywall anchors and the bolts self-thread into the inserts? I guess I expected it all to be a little more sturdy, although I understand all the load on the end stops is lateral... Thanks for your time!