Tense

Please tell me if the tense highlighted is correct.

Tony: I bought them last week by phone. I knew tickets would be hard to get because I had seen a news interview with a group of people standing in line to get tickets. They had been waiting in line for almost a month to buy tickets for the first showing.

Lars: I don't believe that!

Tony: It's true. They had been camping out in front of Mann's Chinese Theater in Los Angeles for about a month because they wanted to be the first people to see the movie.