The clips are listed separately, and the Civic ones don't have an end cap as such as they slot into the vertical trim,
however there are other Honda end caps that fit.
Both ends of the strip require cutting to the angle of the mirror plastic (with a hacksaw ) and the door end , and then smoothed with a sanding
flap wheel on the angle grinder, but this needs extra care and attention, if you dwell on the strip for any longer than a couple
of seconds at a time the heat will melt the coating on the strip, it does sound like a lot of faffing about but its not that difficult really,
the end result done properly is miles better quality than the originals.
The clips needs need a small plastic strip heat welded to the base of them, easy enough job if you have an old soldering
iron and an outdoor area with a breeze to keep the fumes away from your beak!, or... you could get the moldings and shape them to the
correct curvature first, then let me know and I could send you the 8 clips already modified, with the end caps.
Amazing the helping hand we lend to each other on here eh!..

...well, some of us

.