Currently the keyboard driver just assumes that the keyboard has all locks off (caps lock, num lock, scroll lock?), so if you start up the OS while num lock is on, the behaviour of the driver will be reversed: when the num lock LED is on the num lock is off, and vice versa.
Unfortunately it seems like we can't query the LED state of the keyboard on startup, but this is only based on a quick search, someone might be aware of a way.
This means that there are two things which can be done:

1. While there is no support for getting the current LED state, you can send a command to set the LED state. But this might be annoying to use, and I am not even sure if it will work in QEMU.
2. At least for num lock, assume the default state is on. This is only based on my experience of always having num lock on - and I might be special, so this is only if other people do the same. Maybe this could be configured.