Adding key cylinder

Hello there. The 82-310 Key Lock Cylinder should be compatible with this handle set. If there is a punch hole you can remove on that outside pull, it's a simple matter of using a punchout tool to knock out the hole and then install the key lock, and then cutting down the spindle on the key lock so it works properly with the door. The guide below explains. 

Guide: How to install the 82-030 Handle Set

Alternatively, if the thumb lever on the inside pull is perfectly centered between the mounting holes, then you could just buy a keyed 82-030A Handle Set that has the key cylinder already installed.