Abstract: A cylindrical lock assembly (20) includes an inside subassembly (22) and an outside subassembly (24) which are assembled with a door (326). Each subassembly (22,24) includes a rose liner (26,38), a return spring cassette (28,40), a rose (30,42), a lever (32,46) and a lever insert (34,48). The inside subassembly (22) also includes a turn button (36) and the outside subassembly (24) includes a cylinder lock (44).Cylinder lock (44) includes a plug (114) within a shell (112). A rib (122) for supporting tumbler pins (428) is formed with the shell. An identifier actuator (456) is depressed by a tailpiece (116) when a turn button (36) is operated to lock the assembly (20). When the actuator (456) is depressed, an identifier pin (436) is moved within the plug (114) and extends partially from the front of the plug to signify that the assembly (20) has been locked from the inside.