Hey-hey @swcollings, welcome to the Baserow community!
The Airtable import feature is still in beta mode, and its functionality is currently a bit limited. Unfortunately, we don’t support automatic lookup importing yet, and yes — when you would try to change the field type from text to lookup after import, it will overwrite the data. We plan to extend this functionality, but not in the nearest future because you can easily create the lookup fields. Would it work for you if you leave data as the text field type and create a new column with a lookup linking that data manually? We know it’s a bit annoying, but can you use this scenario as a temporary solution? 