The version of the OS is rumored to contain no 64-bit code except that necessary to get the CPU up and happy. Basically, the idea is to bridge the gap until the 10.3 (Panther) software is available in September (estimated).
This would hardly be the first time for Apple and they have a good track record of incremental (and sometimes significant) performance releases, especially in the OS X series.
The eWeek article places a late-July timeframe on the OS and hence the earliest date on the 970 shipments. Although this is a month or so after the current MacRumors info, it is probably a more likely timeframe.