Ended up opening a TAC case anyways.. The answer is quite simple though somewhat obscure:
"To upgrade to a specific version, you need to choose a version number in the policy. From the AMP console, Management > Policies > Edit the relevant policy > General > Product Updates > Set the Product Version to 1.3.1. You will also need to set a Start and End Update Window > Update Policy.
A few notes—while you need to set an update window, you can (after setting the product version) “Download Connector” and it will download the 1.3.1 version. So this upgrade is multipurpose. You can set the product version that you can manually push the update (by Downloading Connector), or you can set it to install via the cloud update. If you choose to update via the cloud, you’ll want to make sure that General > Client User Interface > Start Client User Interface is checked, as this will ensure a “need to reboot” prompt on the endpoint after the update. If it is not checked, you’ll want to check it, and wait for the policy to sync before pushing the update itself."
I just set and update window far into the future then, after downloading the desired version, i just got rid of the upgrade setting in the policy. voila..ready to manually deploy to the test candidates.
