So did Dr. Ivins really send the anthrax letters?

The FBI thinks the late Dr. Ivins is the anthrax killer. They seem to base their suspicions on a genetic match between anthrax in the deadly letters and anthrax in a jar in Dr. Ivins laboratory. Ivins, was a civilian scientist working for the Army on anthrax and anthrax vaccines, so having a jar of anthrax in the lab is to be expected. But I thought anthrax was anthrax, just like the common cold is the common cold. Does each germ bear a unique genetic fingerprint that makes each one different? Or in actual fact, does every anthrax sample in the world match up genetically? Does anyone really know?
Given the FBI's terrible track record (the Richard Jewell case, the Waco case, the Wen Ho Lee case, the total failure to forestall 9/11) and the ambiguity of the genetic evidence, I remain skeptical.