I had requested that my LOR's be properly equipped with my amcas#, but somebody at school dropped the ball. The result was that instead of having completed applications in September, I had to rush in order to get a second copy sent before the December deadline (I would have never known that my file was incomplete had I not gotten antsy and called the admissions offices). Unfortunately, I only applied to 7 schools, and a late (in the process) application did not help me a bit. I lucked out and was eventually interviewed by three schools (in late March and early April), waitlisted at two, and accepted at one. It may be that you can get by without the ID#, but I would make sure that you call the schools regularly until you are certain that your app. is complete. Good Luck!
Frost