Question : Need to use Group Policy to configure computers in a specific OU to use a hardware applience to syncronize time (NTP).

I need to configure all the computers in a specific OU to syncronize there time to our time sync server through group policy.

Answer : Need to use Group Policy to configure computers in a specific OU to use a hardware applience to syncronize time (NTP).

Again: *why* exactly would you want to do change something manually that's by default already setup and configured as it should be?
You're using a domain, so you only need to configure your PDC emulator manually, nothing else (assuming you didn't interfere with the time service before, and that your machines are running W2k or later, but NT4 won't process group policies anyway).