maybe like a lot of other sports stores, if the demand has not been there for that particular style ( checkered) of gun, then the store would not carry it in stock. There are so many types and styles, they cannot carry them all. Why stock a gun that is much more expensive and not have it sell. The "special " looks of a gun these days do not overpower reliability.....checkered stocks do not improve function nor accuracy....
Also in the SIR ad...it does not say checkered stock...as it does in the description of gun below it.