Do I have to re-lock my bootloader to update using OTA?

[NoahWL1]

I want to upgrade to Android 4.3 on my rooted and bootloader unlocked nexus 7, and I'm wanting to use the OTA update feature. I know I need to unroot to upgrade using OTA, but do I need to re-lock my bootloader? I really don't want to wipe my device while re-locking it. I'd appreciate a fast reply because this update not if action in my status bar is driving me crazy! Thanks!