This has been discussed a bit but:
1: They were supposed to be like this but being functionally human they did exactly what human minds do. They individualized.
2: all clones had names even low-level grunts.
3:Here is a list of a good portion of clones that have been made: http://forum.clonecommandos.net/index.php?topic=1718.0
(They may or may not have missed a few)