I have an S7 and need a lock for security., do I have to buy a docking station?

There is not an actual lock slot, but there is a place for a tether or lanyard to connect to the Chassis that can be locked. This is a small hole on the right side of the computer at the bottom of the lower case behind the USB ports. 

http://community.acer.com/t5/Ultra-Thin/Acer-Aspire-S7-391-Lock-slot/td-p/286902