They do move, they will slide opposite the high spot where cam and rocker face meet. If you look at a used 911 camshaft the lobes usually show wear on one side, this is because the rocker mates unevenly with the cam.
One thing you should check 'while you are in there' is the length of the rocker shafts. The very early ones are 18x48mm, the later ones are 18x53mm. You probably have the later ones as I think the changeover point was for the 1967 model year. My '66 had a mix of both. The factory changed over presumably to spread the side load over a larger area and improve sealing of the shaft.
And yes you should check the torque. As you probably know, in 1967 the factory changed the rocker shaft pinch bolt to 7mm from 6mm diameter. The early narrow diameter bolts would stretch into the plastic range and not hold the ends of the shaft expanded against the rocker bores and they would walk. M5 is the size of the internal wrenching feature, screws are usually referred to by the diameter of the shank (thanks Jim Sims!)
I wouldn't be concerned unless there's a lot of movement which would suggest that the aluminum cam carrier bore is distorted. This isn't very easy to check on the car, though. With the shaft and rocker removed you can kind of get your finger in there to see if the bore is roughed up, scratched, distorted etc.
More here on pinch bolts. Keep the SWB faith!
http://forums.pelicanparts.com/showthread.php?t=343519&highlight=inbus