New noise from a new engine

I got the intake manifold off, hoping to maybe find a lifter upside down or something else obvious. Nothing looks collapsed or out of place, but these lifters have the oil hole on the side, so I would think either way is ok. I have no reason to think they’re not original.

Is there a foolproof way to check them, or I can replace them all with Melling units for a couple hundred. What I really don’t want is to put this thing back together and have the noise still be there.