I disagree Cab, I believe Landy first used those clamps along with his 'Landy tool' to swap out broken valvesprings in a hurry between rounds. Makes it easier to keep the rocker out of the way if you don't have to fight against a spring. Look at the way the pushrods are angled. They side-load the rockers into the stands, not away. The engineering department would have performed thousands of hours of valvetrain testing. If they had observed the Gen II needed sleeve spacers or clamps on that spring side, it would have been born with them.

A good test would be a back to back dyno pull with the clamps installed, and then with the clamps removed to see if there is a significant difference in power. Or if someone would run one with a camera and strobe installed in a junk valvecover.