Unfinished drawers are raw and have nothing added to the surface of the wood. The plywood and solid boxes are assembled, sanded and ready-to-finish
Pre-finished drawers have been finished before assembly. This means the drawer side material is finished before any cuts are made. Dovetails or lap joints will have a raw edge where the cuts have been made. If you want a completely finished product, order finished after assembly.
Finished after assembly is the best quality drawer you can find. After the drawer has been completely assembled, the High Quality Finish is then applied. This gives you an absolutely beautiful looking drawer. No raw spots, just a perfect smooth finish on all sides.