The huge glasses Glenn Close wears in the movie are "Mamaw's" actual frames. The family loaned them to Close during production.
Original author JD Vance's family were on set from time to time and Glenn Close has said that she was gratified to see one of his brothers break into tears while he watched her capture the essence of their grandmother's character in one particular scene. After that experience, Glenn knew she'd nailed it.
When Usha is talking to J.D. on the phone in her apartment, photos of the real Usha and her family are on the refrigerator and in picture frames in the background.
A list of popular cuss words and insults that Mamaw Bonnie regularly used were submitted to the production company by the family. Some, though popular behind the scenes, were too much for public consumption.
With her nomination for this film, Glenn Close officially ties Peter O'Toole's record for most Oscar nominations for an actor (eight) without a win.