Pushrod question... Will it cause damage???

Completely correct. The original question sure left alot to interpretation. Especially when implied that the wrong ones were possibly installed....

"Can I reuse stock pushrods if only decked .004?"

Is a completely different question than

"My dad found some mystery pushrods on the shelf in the garage and installed them in "Engine X"...and I now need to know... will it smash 16 valves on fire-up?" Lol