I'm guessing the yellow one is quite late?? Mine is the same (1997) but red, with the vertical cylinder air duct in the fairing. Great looking bikes! Had a spin again tonight on mine, never ceases to make me smile! G.
Yours is a late bike, as you say they put additional cooling ducts to aid cooling to the real cylinder.
Despite what MCN say I think they're a great first bike. Just enough poke to be fun and brilliant handling. I'm looking around for something bigger at the moment to do some longer trips on, but I think I'll keep the 600 for the time being. I think it's one of those bikes you end up regretting selling