That's fine if you have a non adjustable valvetrain. I go in my V/Cs a handful of times a year to check my lash.

I like to use rtv to glue the gaskets to the V/C only. Then they come off the motor clean and when they need replacement (I also like the rubber ones) the cleanup happens only on the bench- no rubber crumbs fall into the motor.

Side note- I had a set of cast covers on a smallblock that would leak but only when I drove- not at idle. Turns out my air-gap's raised runners were barely hitting the inside edges of the covers and looking good but not quite compressing the gasket. I had to relieve (grind!) them a little to clear the runners so they would sit all the way down.