Karl,
No, they were offered from the factory as an option. I have an early (56) small mouth and they have a pre drilled scuttle with bolts in place. The problem is the Brooklands made today are a dif size/mounting system so I had to drill anyways. When you get a Bklnd kit you'll see how to do this. Leave your wind screen in place and put the brooklands mounting posts in place and mark the drill holes. Then remove your windscreen and drill away. That way you can dismount the screens proper(allen screws) and leave the mounting posts in place on the scuttle with the windscreen in place, or leave the whole deal in place. That will make sense when you get a kit.
The windscreen was designed to come off quickly for racing, for my early it's 4 captive screw turns and off she comes, piece of cake. Same to put it back on.
They are like a bike with a fairing, just great, I have not had the screen on in two years (Arizona).