When I started switching out my incandescent bulbs for LED I noticed the side markers on the front didn't have any kind of reflector they were just flat pieces of rubber that the lens sat over.
Needless to say you can see on the driver side picture it wasn't very visible. Now the passenger side one is with the new reflector and its a lot better looking even in broad daylight.
I used this https://www.dormanproducts.com/p-4124-85814.aspx for the bulb socket as it friction fits into the assembly with out issue.
Assembly as fallowed
Grommet 1 for body side
Housing put into grommet 1
Grommet 2 ontop of housing
Install factory Lens (printable lens will eventually come when verify screw heads fit correctly)
may be used on the rear but recommend using flex seal spray on the back of the reflector housing AND bulb socket together as one piece to reduce risk of water short out.
Hatchbox / M3D / ABS / TPU /
White / Impact black
Print the grommets at .2mm with 0% infill your favorite high temperature resistant TPU (M3D Tough Ink should be able to handle the heat)
Also the grommets don't need supports or rafts.
Print the housing in ABS at .2mm (or lower for a better smoother finish) with supports an rafts.