When you have the Import/Export Role you can set up which fields should be mandatory for Export.
And decide if Barcodes have to be assigned before you can export SKUs.
MANDATORY FOR EXPORT
You can decide which - if any - Style header fields are mandatory for Export and thereby has to be set for you to be able to set any Style to Ready for Export.
You can make any combination you need.
If any User with the Integrator role tries to set a Style that does not fulfill the settings to Ready for Export - then that will not be possible.
BARCODES MANDATORY FOR EXPORT
In the same way, you can decide if Barcodes need to be assigned before a Style can be set to Ready for Export.
If you set the checkmark - then you can not set Ready to Export unless Barcodes has been assigned.
If you omit the checkmark - then Barcodes do not need to be set in order for you to set any Style to Ready for Export.
And you will be able to export the SKUs from your Custom Report.