Yes, the pv6parmod module's dc variable is an output, and the value of its "required" field is an asterisk, indicating that it is required.
I suspect that all of the output variables have an asterisk for the value of the "required" field because all SSC variables have a "required" field regardless of whether they are input or output variables, the field must have a value, and for output variables, it makes more sense for the value to be required than not required.
Update: The required field for output variables means that the SSC module will always assign it a value. For now, all output variables are "required" (required = *), but we may change that in the future. For example, for the pvsamv1 module, we could make the hourly outputs for subarrays 2-3 not required (required = ?) so that the module only assigns values to those variables when more than one subarray is enabled.
Best regards,
Paul.