Hi leyakoreya ,
Thanks for your post.
I understand that you want the column GTIN/UPC/EAN/ISBAN to appear in Stock Central (_global_unique_id). Am I right?.
If so, unfortunately, it is not available, and we don't plan to add it for the moment.
In any case, if you consider it necessary, please add a thread in the Suggest a Feature section requesting it. If enough people are interested, we'll consider adding it in the future.
Best Regards,
José Andrés