If you pick the .txt file generated contextually with the latest version of your license, you’ll see the following section, with the number of objects purchased (for which the fee has been payed) and assigned (for which an ID range has been chosen):
Custom Area Objects
Purchased TableData…: xxx
Purchased Report…: xxx
Purchased Codeunit…: xxx
Purchased Page…: xxx
Purchased XMLPort…: xxx
Assigned TableData…: xxx
Assigned Report…: xxx
Assigned Codeunit…: xxx
Assigned Page…: xxx
Assigned XMLPort…: xxx
And after the list of ID chosen for every object type:
Object Assignment
Object Type Quantity Range From Range To Permission
TableData 6 50000 50005 RIMDX
TableData 2 50012 50013 RIMDX
Report 1 50150 50150 RIMDX
Report 7 59100 59106 RIMDX
Codeunit 19 50100 50118 RIMDX
Page 3 50000 50002 RIMDX
Page 2 50028 50029 RIMDX
In this way you can check if the ID you pick for the codeunit is allowed by customer license.