The odom topic represents more then just the "pose" of the mobile robot. If you check the message definition of nav_msgs/Odometry (which is usually used for this kind of message), you see that it also contains the current velocity, as well as the respective uncertainties.
About amcl, though... amcl neither subscribes nor publishes the odom topic (as per the wiki). So the answer to
would be no. Seems the odom topic comes from somewhere else. You can use the amcl_pose topic for that, or use the published transform.