Looking through the other SensorDevice implementations it should be the case that the period in the ExperiementConfig returned by getCurrentConfig() or configure(request), should have the period set to be the minimum period supported by the collection of sensors in the config. You can see this in the PascoUsbSensorDevice#getCurrentConfig method.
However the LabQuestSensorDevice currently just uses a default value for this period. To implement this for the labquest you should look at how getSensorName is implemented in LabQuestImpl. It is reads in a "data sheet" from the sensor and then pulls the name out of it. The are several other fields in the data sheet, you can see them in GSensorDDSMem class. One of those fields is: MinSamplePeriod.