Hmmmm, no step means 2005, no holes on heat shield (yes that's the one) means 2005.5. I wonder if one of those is not original. Mine had both correct so I never looked any further.
I read they widened the rear wheel from a 4" to a 4.25" as well.
The .5 engines had a number of internal upgrades (clutch, oil jets, etc) and one major downgrade - the starter torque limiter.
and get to work on the bike. Do the needed maintenance and TSBs and you are golden.