Sophie Lancaster, 20, was kicked and stamped to death by Brendan Harris, 15, and Ryan Herbert, 16, in Stubbylee Park in Bacup, Lancashire, last summer.
The pair turned on her as she tried to stop them and three other youths from attacking her boyfriend Robert Maltby.
Three judges will consider the sentences of all five at the Court of Appeal on Tuesday.
In April, Harris, who was convicted of Miss Lancaster’s murder after a trial, was sentenced to life in prison, with a minimum term of 18 years before he can apply for parole.
Herbert, who pleaded guilty to murder before the trial, was also sentenced to life with a minimum of 16 years and three months.
The pair were also convicted of causing grievous bodily harm with intent over the attack on Mr Maltby, who has been left mentally and physically scarred by his ordeal.
Brothers Joseph, 17, and Danny Hulme, 16, were sentenced to five years and 10 months each for their parts in the attack, while Daniel Mallett, 17, was sentenced to four years and four months.
On passing sentence at Preston Crown Court in April, Judge Anthony Russell QC described the attack in August 2007 as “feral thuggery” and said the boys’ behaviour “degrades humanity itself”.
Miss Lancaster died in hospital 13 days after the attack.
Her mother, Sylvia, now campaigns to help raise awareness of different subcultures among young people.