The Web Viewer install in the 14.0 CA View install is for MTC Content Viewer AKA 14.0 Web Viewer.
12.1 Web Viewer is not installed from the CA View install. 12.1 Web Viewer has its own, separate install.
Release : 12.1
Component : CA OUTPUT MANAGEMENT WEB VIEWER FOR ALL PLATFORMS
Web Viewer 12.1 needed to be installed.
Use CSS Tomcat from CA Common Services. It was this second option that was utilized to to have the Common Services distributed Tomcat host the new 12.1 Web Viewer install.