Are new valve locks necessary

No they are a single lock with the lash cap groove showing above the worn out ridge , stainless ferrea valves in RHS heads .look at the edges of the half shell and you can see there is only a millimetre of material left of what was about a 1/8th" ridge the rest has sheared of flush with the lock id .

Ah, thought one ridge was sheared and the other part way gone.