If there is any metadata attached to an Item in GatherContent, it can be imported to AEM as well.
Add metadata fields
You should add metadata fields to your GatherContent Templates just like any other fields that you want to be mapped and copied during the import process.
Metadata fields should be mapped for every language independently of any other content.
Once mappings are specified the content can be imported via the Import function.
Imported metadata can be found in corresponding page properties.