the HDD area will be empty but will also be missing the cable, so you'll need to get the cable if you want to add a hard drive.
Theres no way to change this, its because flash storage and Solid state drive are similar but not identical tech, just be honest when you resell and say you replaced the drive.
Once they have, you'll be able to view a graph of their reputation gained over time.
Here's a preview of what the graph will look like:
No reputation gained yet.