Does my employer have to pay me for time I did not record?
Yes. If your employer requires you to clock out before finishing part of your job, you are still entitled to pay for that time. If the employer knew or had reason to know that you were working, then you are entitled to overtime pay. For example, if your supervisor knows that you always clean up the shop for 15 minutes after you clock out or you have to fill out inventory or other paper work after your shift and turn it in, then your employer likely is aware of this activity and you should be paid for it.