Anyone know if these bolts thread out or are they hammered out from the bottom? The tab makes me think they hammer out from the bottom but I gave them a couple of hits and they didn't budge. Then put a socket on the bolt head and got no joy. Since this back piece is aluminum I didn't want to go too hard on the hammering or the socket until i knew for sure. Its an early dodge NV4500 if that makes a difference. Thanks!