Unfortunately, no. SIGFOX is a great network however there is no QOS and the mcDemo205 cannot receive downlink messages (too costly on battery consumption) so there is no way that the device can know if it is in coverage at all.

There are some easy example projects available in the mcDemo205 documentation where you can send messages and then see if they are received on the SIGFOX backend. Alternatively, you can check the coverage map (www.sigfox.com) to ensure that you are in a covered area.