a compression test requires cranking the motor with a pressure gage stuck in the spark plug hole, so yes. If there is a knock, different ball game.
Before rebuilding this motor, look into buying a used one from a reputable junk yard.
The newer v6, from 92 to 2003, are MUCH better engines....problem here, tho, is the intake manifold. There are none for Throttle Body fuel Injection for the magnum v6. THere are maybe a dozen made to be used for carb or TBI with adapter plate. I had one of the few, and I sold mine a few months ago.
The v6 just isn't that popular an engine so performance parts are not available...
The best bet is to drop in a 5.2 magnum v8. There are carburetor intake manifolds for them that you can put an adapter plate on top of, and use your TBI. The 89 Shelby dakota had a LA version of the 5.2, and it used the v6 front springs, so this is an easy way to get serious horsepower in your truck. There won't be room for a fan blade so you will have to put an electric fan in front of your radiator/condensor. DOes it have air conditioning?