Why not just drop the motor and have it checked and milled? Let them reman your crank and check out the bottom end. Then you do the rest!
I've always just pulled em out and taken the short block over to NAPA machine shop and let them do their job. Then get everything back in pieces and put it together. Do a head job and put in some GOOD head gaskets and finish.
The problem with just swapping is you don't know if it's a main bearing, rod bearing, or wrist bearing. But you could pull the pan and see what the Main/rod bearings look like and go from there. Maybe you will be down in the copper and just a replacement bearing set will do for another 50K or better.
The main thing firt is to pull the pan and see wht you got.....And post pictures here!!!!