Certainly.
Now I suppose you want to know how..
note that if you habitually keep disks in the floppy drive or bootable CD's in the CD drive.. they will get in the way of a reboot to the hard disk.
Under OpenServer I like to add a line 'TIMEOUT=10' to help shorten the default 60 second timeout at boot time where the 'boot:' prompt waits for a keypress before auto-boot kicks in. I add this line to /etc/default/boot.
Use cron to schedule the time to reboot. 'man cron' for info, 'man crontab' for info on editing the files controlling cron.
heres a line to example rebooting every sunday night at 10:15pm:
15 22 * * 0 /etc/shutdown -g0 -y -i6
Now, I run OpenServer, so my example reflects that. -g0 means shutdown immediately, -y means answer yes to the 'shutdown now?' prompt, and -i6 means goto init level 6, which is a shutdown and reboot.
Now.. having said all that, there is really no reason you should ever need to have your SCO box doing automatic shutdowns.