Here's a SD Myres that I just got.... it's marked with the number 999 under the holster on the skirt. It's very, very similar to a BBQ rig that Dan M posted back in December of 2010 marked "190".
It appears to be for a 3 1/2" to 4" barrel. The N frame is a little tight and a K frame is too loose. I'll set up some pics later and see what the consensus is.