I picked up a set of Pro Series Magnum Gobble Dot sights for my 870. Out of the pack, the screws were locked down on each sight, but they just sat loosely right over the rib on the barrel. After backing out the screws I see the sides are fixed... what in the world's the point of the screws. I used the "spacers" the pack came with and now the sights fit snug on the rib, but something's just not sitting right with me. Anyone else had this issue, or have any suggestions?