Ha yeah, I just had to put mine back on too. That happens when you rub your body against the rubber gasket when you exit the vehicle in tight circumstances. On mine it just happened during the state inspection and I was getting out of the truck while it was on a lift. Not enough room to actually get out of it at all.
So, what you have to do to put them back on the plastic T shaped pins is to put one side of the T into the hole in the rubber. Then stretch the rubber up enough to slide it onto the other side of the T. It takes some effort on the stretch of the rubber but it'll go on . A few tries and it's all back together looking the same as usual.