Good catch! I have a sc52 and a sc52w - both of which were from the first batches of each - and they are both the same as the top one in your picture.
I notice that not only does the bottom sample have more rings, it also has more protruding in front of the cut-out rings after the head size slims down to accomodate the press fit bezel ring. Perhaps the reflector/bezel ring appear different too?
There also appears to be a narrower section on the new one just before the body size increases for the clip mounting position.
I assume the UI is the same? That is, you don't have the newest interface where three quick clicks from off go into strobe mode?
Edit: does the one with 9 rings feel like the edges are as sharp around the switch recess and other places?