Absolutely. The database edit affects all offline modes. However, do not attempt to go online with these modified files.
If you have a "No-CD" or "Cracked" .exe file (often required for offline play if you don't use Origin), some cracks hard-lock the kit menu.
Solution: Find a specific "FIFA 14 Reloaded Crack" version 1.4. This version supports database mods. The standard 3DM crack does not.
If you want to manually force the game to wear specific classic kits without replacing current files, you can use a Cheat Table (usually for Cheat Engine). This is common in the FIFA modding community. how+to+unlock+classic+kits+in+fifa+14+pc+offline+full
Before modifying any files, navigate to Documents\FIFA 14 and copy the instance folder to your desktop. Also, backup the Game folder inside your FIFA 14 installation directory (usually C:\Program Files (x86)\Origin Games\FIFA 14).
There is a famous hidden kit in FIFA 14 called the EA FC 14 All-Stars Kit (Black kit with white EA logo). This is often what modders look for. Absolutely
Steps:
This method is for power users who want to avoid third-party software entirely. Before modifying any files, navigate to Documents\FIFA 14
Drawback: This is tedious for over 50 kits and only recommended if the above methods fail.