Should an engine be torn down after a prop strike?

To answer the question "should the engine have been torn down for a more complete inspection"?

My recommendation has always been to do a tear down inspection for the following reasons:

After a prop strike there is rightful concern about the airworthiness of the engine. This concern can only be answered by inspection and not by hope, prayer, or opinion.

Having a shop that has performed approximately 1 prop strike inspection each month for some 20 years, I still cannot tell you which prop strikes cause damage and which ones don't without an inspection. This has taught me that the perceived "severity" of the propeller strike is not a criteria for deciding which engines should be inspected and which ones need no inspection.

I personally didn't tear down my engine after I hit the tow-bar with the propeller and sent it flying across the airport. But then we did one on a Navajo that hit a plastic caution cone that had damage -

That said, my opinion is based on my personal experience. Others have views that conflict with mine based on their experience and judgement. I could be wrong.

I have spend many year pondering how to inspect the engine without tearing it down and I have never come up with an adequate method. Your question as to signs to look for - I don't know.

Interesting things found in the course of doing 500 engine tear-down inspections:

Crankshaft's can crack and not be bent - dialing the flange won't reveal a crack.
Engine mounts can be bent.
Big Continentals with gear driven alternators - sudden stoppage even at low rpm can crack the crankshaft at the alternator gear attachment. There is a lot of energy stored in that large rotating mass.
Pieces and bits of a Craftsman 9/16 inch socket found inside the engine.