WELCOME ABOARD!
U-Mark, as it's called, can be easily restored, but I'm not at my own computer right now and don't want to give you the wrong facts. Someone will be along soon with the correct answers.
The ID book has chapters. Click on the left-right arrows to access different nations' merchants. Also, If you are using Weapons Officer Assistance, or auto-targetting, once he has identified it for you simply click on 'Ship' on the notepad, and it will come up by itself.