I saw that there is a different image sensor for the gc2 and gc3 from alarm.com. I’m thinking of upgrading to the fc3 but I have 2 image sensors on my current system.
That is correct, the GC2 uses a different image sensor model than other panels. Upgrading to a GC3 would require replacement of the Image Sensors, or at least the existing ones could not be used.
The GC3 Image Sensor can be found here.
Thanks