If you want to see just the leads that you've imported, you can reveal the column called "Imported".
Once, the "Imported" column is showing, you can bring the imported leads to the top of the chart by clicking the column-title "Imported". The value of "1" means the Lead was imported. The value of "0" means the Lead was acquired via a Growth-X acquisition campaign.
With this view showing, you can verify which leads were imported, and which were acquired via a Growth-X acquisition campaign.