It is very possible the rockers havent been replaced or reserviced for many thousands of miles. If that is the case, they WILL have wear pockets at their end from valve contact. You can adjust the valves perfectly by feeler gauge, and they still will be extra loose by the depth of the pockets. So while you are in there take one of the adjusters all the way out and run a finger on the contact surface, or use a dentist's mirror and take a look at the end of one, to get an idea of their condition. They all will be basically the same with regards to wear.

Any auto machine shop can resurface them for not much, especially if you dissassemble the rockers yourself.