It's very hard to second guess the "Quality" of the build. Obviously it was not rebuilt, maybe not even re-ringed. The bearing issue is the best example of very low grade work in any case. Now the rings will need to be removed off the pistons to make sure no contaminants still remain. Simply blowing the rings out you can't "know" all the trash is out. "Knowing" every aspect of the assembly process is how we warrant our work. The rings must go back on the same piston and in the same groves. If you do take the rings off place them 1/2 way down in the bore, use a piston to "square" the ring with the cylinder walls and check the gap, of Every Ring. If you find any tight rings they should be ground to the proper clearances too. The pistons must go back in the same hole, also they are usually oriented in a particular direction so pay close attention to that or you will have a severe case of "Skirt Slap" if not a complete binding of the rotating assembly. Plastigage the bearings, pressure wash the block super well, I noticed no Anerobic Sealant in the block halves, if that is required I suggest using it instead of the RTV that was used to begin with. Use a Torque wrench to reassemble. The oil pump almost has to have damage I wouldn't think of reusing it. Finally one cylinder had low compression that I have not seen a "Why" posted yet. That must be fixed. My Bud.