I know that GM has discontinued the SS axles some time ago. I saw this on Ebay yesterday. I sent them my 2009 SS VIN and they say these are designed for the SS. Since they are the same length, they said to simply order two if you need both sides. These are for the automatics. Looks like they are stocked in CA.

https://www.ebay.com/itm/FRONT-LEFT-DRIVER-CV-AXLE-GSP-FIT-2008-2010-CHEVROLET-HHR-L4-2-0L-AUTOMATIC/333813115777?hash=item4db8cfeb81:goUAAOSw3olfyYw D

 

I thought it was the 5 speed manual transmission axles that were discontinued and are now back in stock. Or a company was rebuilding cores sent to them.