I’m looking for a place in Los Angeles that seedlings parts like tailgate and interior stuff. 

Salvage yards, Pick a part, etc.

 

LMC truck sells all new stuff.

https://www.lmctruck.com/

Check these out.  You might have to travel ; there are a lot of places in Riverside County.

 

https://www.autopartswarehouse.com/?msclkid=88c2a9cab849130d29fcf7aba548e682&utm_source=bing&utm_medium=cpc&utm_campaign=[ADL] [Brand] Brand Terms (Exact)&utm_term=auto parts warehouse&utm_content=Auto Parts Warehouse&gclid=CP2U_6zVg-gCFaKUxQIdYX4Mbw&gclsrc=ds

 

https://www.lkqpickyourpart.com/