Try and see. Like i said for me it never worked and it doesn’t help for security if you lost it.

Try doing the command:

uqmi -d /dev/cdc-wdm0 --verify-pin1 <pin>

Experiment using SSH, not in the GL-iNet interface for this more advanced things.

Some more info:
https://wiki.openwrt.org/doc/recipes/ltedongle

And do

uqmi --help