came with all sides of the openings covered with a nice little white trim except the side that the hinges are on. The reason there is no trim on that side is because a wooden backing is put on to keep the screws from working there way out and the trim is not wide enough to go over it. The factory had told me this when I was cutting a new door opening to be sure to back the screws with wood as they don't tend to vibrate out as much as they do when screwed into only fiberglass.
The overhead cabinets doors hang from the top consequently I was busting my knuckles on the raw fiberglass edge nearly every time I went into them. I wanted the trim to match so I ordered several lengths of trim from the factory. Since it's "U" channel and not wide enough to fit over the fiberglass and wood backing I simply cut the back side off making it an "L" channel. I had to file it down a little where the hinges are just to make it a little thinner so the door would close properly. I adhered the trim to the cabinet with contact cement.
Works great, looks nice and it all matches.