The front rotor on the K5 above looks more like a K3/K4 part. It's a Suzuki studio pic so it's probably preproduction, i.e. K5 & K6 used the same rotor. Here's one, apparently even earlier, where the lettering on the muffler is different:
^In your first pic you can see a slide of the back-torque limiting feature of the clutch, new for K5.
Your final pic looked fishy and I was about to call it as for some other model. But then I found page 6 of this 2007 catalog (also see 30-31). There are two supposed pics of the 99000-79N12-021 exhaust for K5/K6. Both are suspect. The top pic is a K5 but in 2005 the only exhaust was 99000-79N12-007 (non-catalytic and later replaced by 99000-79N12-021). It has a mounting strap around the muffler and the emblem is towards the front. However the lower pic, supposedly the same exhaust, shows a welded mount with the emblem towards the rear like yours. I don't think the welded mount ever made it to production so my best guess is that both pics are of a pre-production system that was never sold.