Parking Lamp Gaskets

I’m replacing my front parking lamps on my 71 Dodge Dart and it came with new gaskets . The rectangular ones are for the perimeter but what are the round ones for. I assume the bulbs? If so do they get glued in place since there doesn’t seem like there’s any way the will stay in place otherwise. Are they necessary? There aren’t any there now.

Appears so according to DMT's site, probably just helps to keep water out so you don't blow bulbs. Someone smarter can answer about them being glued on though.

I'm not familiar with that fixture. That gasket may go behind, between socket and fixture. Inside wouldn't help. Too close to bulb and it might melt.