Original Interlock Tru-Latch spring loaded Double Hung sash lock with two screw holes. Used by FHA, JELDWEN and others
This cover and mechanism have been updated with newer styles without screw holes.

May be Replaced with Current style with snap on cover.

Related parts:
SK09-0001 Tru-Lock spring loaded sash lock mechanism
SK01-0010 Concealed Screws Cover
SK01-0006 Indicator Cover w/ red strip 
SK04-0008 Slim Line Cover - Plastic 
SK04-0012 Slim Line Cover - Zinc
SK04-0007 Soft Line Cover 
SK04-0014 ADA Cover w/ String
Note: 
Some covers have minimum quantity requirements and are special order