Hello Justin,
It seems like the answer is unfortunately no. Under the hood, Caliper Api is just calling the Hq method. If you know the device nickname and you pass that along it should return an error if that device doesn't exist.
I talked with the team that maintains the Caliper Api and they are going to take this as an enhancement request. They will do a check before sending the notification to see if a notification will go out and if it will go out then they will send it. If not they will return an error. So if you would like more information on that please create a ticket on q2developer.com
Hopefully this helps,
-Trey