Just general wear, typical of high mileage TR3A motors. The shaft had big grooves in it where the rockers rode (on the bottom of course) and the bushings in the rockers were worn out as well. The rocker tips were worn until it was impossible to set the valves accurately. The springs hadn't broken yet, but there were sections where the spring wire was clearly worn (and matching marks in the shaft & rockers). The wear in the adjusters wasn't obvious to me, but I'm sure they were worn as well. And of course the locknuts were all somewhat mangled from the wrench slipping off at one time or another.
The only things they obviously didn't replace were the end caps and pedestals. I have to believe they just reconditioned the rockers, but they looked new as did the shaft.
I learned about them from a "tech tip" originally published in the local club newsletter way back in 1989. It had basically the same spiel you can read on their web site today, about hard chroming and centerless grinding, etc.