If you pull the valve cover and run the engine, you can verify rocker movement and oiling. Then push down on each rocker as it’s running to see if the noise changes.
Other things to try:
Unbolt fuel pump from block and run (won’t run long but it will run and tell you if it’s pump related)...
Had a very similar sound in a 79 I just did. I’d have been inclined to run it if it were mine and see if it changed but we changed it for another engine we found just to be safe.