The type of crimp on British & Empire .303s has varied considerably over the years with time and contractor. There have been a number of other small changes, some of which don't seem to have been implemented in overseas establishments for some years.
Neither of these looks unusual. Looks like one has been heavily polished in the past - what with? (ammonia-based polish?)
South African stuff of this vintage has been reasonably common in recent years and much of it suffers from season-cracking in the necks, to the point where bullets can be rotated or just pulled out.