No worries, better to ask questions now instead of having to deal with Fairphone support (and Cordon, the repair contractor) later 
If you are on the latest stock FPOS release (which you need to be to unlock the bootloader for the first time), you need to be aware of the current patch level:
The available /e/ OS images are older…
/e/OS build : R stable (Security patch: 2022-07-05)
…so whatever you do, don’t lock the bootloader!
Edit: Apparently 1.4.0 seems to be up-to-date and available in stable, so mabye someone just forgot to update the docs 