Are new valve locks necessary

I say "interesting" because there should be zero movement between the groove on the valve, and the actual ridge of the lock. No rotation, no bouncing, nothing. The springs pressure the retainer, the retainer pushes the locks into the grooves, and everything gets wedges together. What that looks like to me is the angles of the locks are wrong (might be a defect), and/or the grooves are a problem, and/or you have harmonics in the valvetrain that's beating parts. Regardless, I would say the locks are potentially part of the problem, but more the symptom of another issue. Just my $.02.