Hi Ronnie,
There are a few Mk2s that only have 1 rivet holding the end screw. These were from the first production run of the Mk2, so I'm not sure whether yours will have 1 or 2 rivets.
Even the Mk2s with one rivet should be OK though. They were manufactured to a much smaller tolerance to prevent the "wobbling" you mention, and the rivets were upgraded for tougher ones. There have actually been a couple of minor improvements even since then to rivets and materials etc., but these have been to satisfy ourselves rather than because we have any concerns over the ones that were sent out.
Paul