The quick test is that the cam rotates freely with the cases bolted together. Like musky says we're not talking microns when considering these castings from 60 plus years ago. If that drive side bush has been replaced, more likely the timing side bushes set the datum and in fact everything is fine as regards parallel alignment with the crank.
But confidence is another matter, and if you can get a refund all to the good, there are perfect cases out there somewhere. The numbers don't look as clear or as good a match as many, so treat with caution. Look for inspectors' stamps on the cylinder face, these are circular and bridge the crankcase joint. If present and complete, this confirms an original matched pair. Stamp a bit skewed? Odd cases with a bush offset to get a runner, crankcase number is artistic licence. Who knows?
Swarfy.