The dust plugs ordered from Amazon finally arrived from Hong Kong (seriously) and this is how they look. I have 8 left over so if anyone wants a couple, PM me your address and I'll drop them in the mail when I get a chance.
They have small ridges on top (visible if you look closely) that help with pulling them out of the sockets.
FYI, the power is not on in this pic but when it is, there's a faint blue glow around the edges from the LEDs in the socket.