I finally received the 3 aftermarket port covers a couple of weeks ago, that I ordered from a HK seller on ebay (http://www.ebay.com/itm/261068304385?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
The DC and USB covers are exactly like those in the pictures above, same plastic, no ridges on the sides, same concave dent on the DC one.
I don't have OEM DC/USB covers to compare, but I can say this:
* first, when replacing the metal bracket under the bottom, one of the screw holes on the USB cover had a smaller diameter, so it would not go in all the way, until I enlarged it a bit.
* the DC cover has to be pushed hard to stay (barely) closed, and even then, it doesn't stay flush. after a short while, it comes open by itself.
* the USB cover seems ok though, remains closed and flush, for now
* the Serial cover: as you can see from the image, the thin part where it bends over the edge, was a real letdown. The plastic turned white-ish after the first time I bent it. It won't take too many open/close cycles before it breaks.
I didn't even bother to mount it (the OEM serial one I have is worn, but still makes a good seal and stays in place).
Plastic will never make a tight seal with metal, rubber is the way to go.
I should have bought the OEM ones from the start, but now I really know why
P.S. Blair, that's the review you asked me for, more than a month ago; at least their color is black