I never ever drop a used engine in a car without popping the pan and inspecting the bearings. I've seen plenty of good running engines with bearings that needed to be replaced. Once you have copper showing, it's only a matter of time until it spins or ruins the crank or both... so it's silly to NOT check it for the price of an oil pan gasket. If the bearings look good, button it up, maybe change out the oil pump and water pump and rock on. If the bearings look tired, it may be time for a rebuild while the engine is out.