Murph, I hope I'm not wasting your time, but I have a Don Hume, plain leather thumb break which I obtained for a mod 5906. Not sure if it will work for you, here is the number stamped on the back H738 SH L NO.5M. If you think it will work I don't need much for it, sorry I am unable to post photos but is in almost unused condition. Forgot to mention, it is for right handed carry.