Dmailer and Gpalmer,
There is no way that I know to tell the difference between the new Silver Ref. and old version from looking at the cable exterior. That is what I asked before sending mine in and they determined by age if they were upgraded or not. The newest pair was purchased since CES and it wasn't even the latest version.
The clear shrink tubing over the silver/gray was a previous change from the original version which they still use on the latest production, as far as I know.
I think the cable is more balanced with enhanced midrange and bass performance since the upgrade. It did not take nearly as long for them to settle in after the upgrade, but you should give new ones 100-200 hours. They may continue to improve with even more time. If you call and talk to Robert, ask about his results when comparing the newest Silver Ref. to Valhalla.