Make sure that you install ePO 4.5 patch 4 hotfix 1 before you install the 6.1 extensions and packages.
The short answer to your question is yes. 6.1 extensions can manage 6.0 clients. This includes all management tasks like reporting, recoveries, and exporting the recovery information.
Awesome! Exactly what I wanted to be sure of before starting a deployment
If you can, please report the experience you have with your deployment. We're very keen to understand success rates, deployment rates, and any specific issues that arise (especially in upgrade scenarios).
Just as a followed to this, our deployment with 6.1 from 6.0.1 has gone quite well. We now have all machines running the new version in fact the number of machines is higher because machines that for whatever reason weren't activating with 6.0.1 started activating with 6.1 so that was a pleasent surprise! The upgrade also took care of mis-matched LDAP strings in our EEUsers table and AD (we had moved a number of users and computers at the same time with 6.0.1) which saved me lots of time.
Overall the process so far has gone quite well.