Hello Earl
An IPv6 interface will compute a global unicast IPv6 address only if the ipv6 address autoconfig command is issued AND there is an active IPv6 router on that subnet. So your first statement makes sense, that no IPv6 global unicast address is computed unless that command is issued on the interface.
Your second statement however shouldn’t be so. If you have the DHCPv6 stateless configuration on the DHCPv6 router configured, then R2 should be able to compute its global unicast IPv6 address. If no IPv6 global unicast address can be computed, then that means that R2 is not able to receive any RA messages from the DHCPv6 router. Can you confirm that your configuration is correct? You can also use the debug commands used in the lesson to see if the information request is being received by the DHCPv6 router.
Let us know how you get along so that we can help you further in troubleshooting.
I hope this has been helpful!
Laz