A judge recommended that a man who spent 10 years in prison for a gang rape be exonerated after a prosecutor acknowledged that his arrest had been a case of mistaken identity. If the appeals court formally approves the recommendation as expected, the man, James C. Giles, 53, will become the 13th Dallas County man to be exonerated since 2001 with the help of DNA evidence. Mr. Giles was arrested for the 1982 crime even though he lived 25 miles away and did not match the description of the attacker given by the victim, said his lawyer, Vanessa Potkin. Investigators ignored a man with a similar name: James E. Giles, who lived across the street from the victim. James C. Giles has had to register as a sex offender since his release, 14 years ago.