The film is set in 1986, but several of the vehicles used, including David Young's white minivan, were 1990s models.
Most of the kitchen appliances and landmarks featured in the film didn't exist in the 1980s. A lot of them are from the 21st century, such as Dorsey's refrigerator and the buildings.
Ron Hartley's squad car can't legally have been registered anywhere but his home county of Lincoln. Lincoln County license plates begin with a 12. Ron's car in several scenes, is clearly shown to begin with a 9, putting its locality of registration, and hence, of origin, in Big Horn County, far away on the Montana border.