Hi,
You can definetly do that.

- You create the Microsoft Office Product as a "Storable Product". On the "Inventory" tab, you select "By Unique Serial Number"

- You add the number of units through the module "Inventory" -> Opérations -> Physical Invetory (Adjustments)

- You create the Keys as Serial Numbers through "Inventory" -> "Products" -> "Lots/Serial Numbers" and assign them to the Microsoft Office product.

- Once you have created a sale order for the product, you will have the Delivery smart button. You click on it and you assign the Serial Number to your delivered product.