Yes, there will be the way he's talking about, but I've never seen a spec for it anywhere. What he means it with the valve closed, depress the pushrod FULLY into the lifter plunger and bottom the lifter plunger out, then measure the clearance between the valve stam and rocker tip.
You need to be concerned with lifter preload. That is the only measurement that's critical there. Lifter preload should be between .020"-.060" with the valve closed. Sometimes with anit pump lifters, you run zero preload or even up to .002" lash. I like lifter preload on the light side around .010"-.020", but that's my personal preference.
