Continuity mistake: When Loretta Lynn is at the radio station asking why the disc jockey had lied to them about playing her record, you see the picture of her that they took at home. It is a completely different pose than the one that you saw them take a couple of scenes earlier. She is looking in a different direction and she is not smiling as much as she was when they took it.
Factual error: When Loretta and Patsy return from shopping, and Doolittle gets mad about the makeup Loretta is wearing, look closely after they leave Doolittle and you will see a 1965 Pontiac Tempest among the parked cars. Patsy Cline died in 1963.
Factual error: Doolittle Lynn is visiting Loretta when she is 13, which would be around 1945. The jeep he is driving is at least a 1949 model. Pre-1949 jeeps had a split windshield. Also the civilian jeep wasn't introduced until 1946, so in his first appearance he would have to be driving a military issued jeep.
Factual error: When Loretta is having her initial pregnancy exam, the doctor tells her he hasn't seen her since she was a little girl getting her measles shot. Loretta Lynn was born in April of 1932, married in January of 1948 and her first pregnancy happened soon after. The doctor scene had to take place mid- to late 1948 or early 1949. Measles shots were non-existent in those days.