Thanks rc.
I did call S&W Customer service and they did send me a screw, but it was the wrong one.
I thought I had described it's location accurately, however the one they sent is a bottom side plate screw.
Maybe I'll call them again and see about an exchange. Or, I may just take it to my local gunsmith and have him repair it.
If you run across a parts diagram for the Model 27-9 I would be most grateful. In the mean time I'll keep looking.
Many thanks,
doublegun