There are Two Ways to tell if a Lead is a Bonus Lead.
The easiest way is with the Bonus Lead Tag.
All Bonus Leads will have a Tag called Bonus Lead.
To View this Tag.
On the left side of the Person's Page is the Information Section.
At the top of the OVERVIEW tab is +ADD TAGS item.
The Second Way.
Go to the Lead's Page.
In the Information Section on the left side of the Page.
Click on the STATS tab.
Near the bottom of the tab, you will see the SOURCE item.
If it says SOURCE Orphan.
That means the Lead is a Bonus Lead from outside of your Territory.