Hi Les,
That looks like a fleetside bumper to me too.
If you look closely at the step/hitch plate you should see a weight rating and GM part number stamped into the metal.
As listed at:
http://www.gmpartswiki.com/getpage?pageid=36736 the GM part numbers for the painted step bumpers are:
14043837 = stepside
14043838 = fleetside
The chrome step bumper #14043836 isn't listed as stepside or fleetside. But I know from personal experience that it is the wider style that is correct for a fleetside.