I think they are glued/pinned on but I could be wrong. flip your running boards over and see how your end caps are attached, It will be the same for the other style of caps.
lol, you just bought running boards, I just removed mine. haha.
they have pretty much been discontinued from toyota so getting them from a dealership most likely wont happen. you will need to scour the for sale thread, craigslist, and junkyards. They were also hella expensive from toyota