'79 440 Motorhome short block - Should I buy it?

The crank number is 4027175-5 and the damper says "Use With Cast Crank Only", so I guess that settles that. Oh well, If I don't try to do anything silly with this motor I should be okay. Several of the rod caps look like they have been machined so that some are flat and some are more rounded. Could this mean that the motor has been balanced or would this be an original factory thing?

Thanks,