Most Toyotas use a replaceable shim to adjust the valves. If the adjustment is off you have to remove the shim, measure it and buy the replacement. With 230k it's a definite possibility.Asking if it was out of adjustment or can a new valve be installed and adjusted instead of new heads or what?? Don't have any more details at this time.
I think I'd fix exactly what needs fixed and carry on or sell it on a 20 YO/230k car but he's a Toyota Fan Boy. It's kinda killing him that his beloved Toyota has failed him at such low mileage.