I can't tell you with 100% certainty that this will work - but it does for my 4" N-frame with a Burris FF III using an Allchin mount. They make it for the 6" L-frame. It is Blade Tech's Pro-Series Speed Rig...
The top is open. Depending on your mount you may have to peel back the ears slightly. Needed no mods with my Allchin mount. Retention is good and you can alter the rake if desired. Also, many belt attachments.