Some stock footage from the 1970s is used.
In a sex scene what a nude Josefin Ljungman was licking was not the real Bill Skarsgård's penis but a prosthesis.
The authors did a great job at reconstructing and lighting to make it look like the film was shot in the 1970s. However, probably on purpose, in the very last frames of the film, when the two main actors kiss each other a car drive by that cannot clearly belong to that period.
While the film mainly takes place in 1975, the title song "Himlen är oskyldigt blå" by Ted Gärdestad wasn't released until 1993, featuring newly recorded Swedish vocals to the backing track of his 1978 song "Blue Virgin Isles". The other pop songs are from 1975 and before, except "Young Love" by Motoboy which is played during the end credits.