Gem car body and paint

I have 2010 E4 (Dark Green) I hit something and have a small crack in the rear fender. I have removed the rear section and took it to a couple body shops. They all asked the same two questions: Is there a paint code? What is the “plastic” material?
Can someone help me?
Thank you,

I’m not sure about the paint code but I just painted a 2002 GEM to where the front is plastic and the rear is fiberglass, the 2 hardest surfaces to have paint bond to. After trying car paint, latex based and acrylic paint (which all immediately started to come off once they were dry) I found Krylon Fusion spray paint works very very good. They have a wide variety of colors, unfortunately of all the colors in the light spectrum green has the most tints so I’m not sure it will be the exact same but since you already have the piece off there’s not much trouble in painting the whole thing. You can give it a little wet sand after and she be good as new you don’t need to primer just wash and paint. Good luck hope you find what works for you.