No, the Regular License is fine. You only need the Extended License if the item is actually part of the product itself.
If the item is used within the free part, the Regular License if fine. If the item is used only in a part that requires payment to access, you need the Extended License.
Example: If you were using a 3d model of a sword for a game and you could only get the sword by buying it, you'd need the Extended License. If it was the starting weapon that even non-paying users could use, all you'd need is the Regular License.