I believe that the three digits from the clipboard are random. These should be entered first, then the five from work assignment.
Double check that your first 3 digits of the code are correct. You'll see at the top left of each of the clipboards that only one digit appears - the two other digits have been defaced. Note the positions of the defaced digits, so you know where the remaining legible digit should be. Apply this to all 3 clipboards and you'll have the correct positions of the digits.
The five from the work assignment is: 21974.
Check carefully against MaG's walkthrough if you're still unsure, as it's important that all clue documents for this part are examined. The lock itself is also fiddly -- the Enter and Reset buttons are set close together.