Can I show a 24-Hour clock on my Mac's Lock Screen?

I just got a MacBook Pro, and different from my iMac is that I'll be using the lock-screen much more on this one. I noticed that in the upper right corner of the lock screen, the time is shown, but it is in 12-hour mode with AM/PM indicators. I guess this is some remnant of the machine having been configured to use english language as the main language (I'm a developer, I don't want to have to fight with badly worded Norwegian translations of error messages on google). I have configured my main user to have normal Norwegian formats for everything, but I guess that on the lock (and possibly on the logon screen as well?) screen, there is some kind of global system-wide configuration in use. So, can I: 1. Configure the lock screen (or the system wide configuration) to use 24-hour clock? 2. Remove the clock altogether?