Hi,
short answer? No, not really.
Now the long answer. After setting up Anti-Theft, PIN protection is enabled in Mobile Security as well exactly because of the Anti-Theft link on Mobile Security dashboard. However, you can disable PIN protection in Mobile Security alone, which would also mean the thief can access the dashboard and tap on Anti-Theft to figure out if it's installed, so I wouldn't do that. But on the other hand, you can also enable PIN protection in Mobile Security if you don't have Anti-Theft installed (for a various reasons, for example you don't want people to mess with your firewall or SMS/Call filter settings). This means that the thief can't tell whether the Anti-Theft is installed or not just by seeing the PIN dialog in Mobile Security.
Filip