No you do not.
Your Dstore licence allows you to get a ready built store at the lowest price in the market.
Once you have a store to sell products from (through Dstore or on your own), you will need products to sell. Thats where your Dropstore licence comes in.
A Dropstore licence allows you access to our full range products, ability to sync products to your new store and orders back to Dropstore.
If you already have your suppliers or products, you may still use Dropstore along with your own products to supplement the inventory you have or choose to entirely go at it yourself.