The 06 i believe is the fz6n
As mentioned before ...07 had some improvements done on it... But also has greater mileage
Check them both out then make a decision
There was no FZ6N sold in North America, it's a home made naked. I'm also wary of buying anything modded, unless it's exactly what I want and appears to have been done well. Far too many people permanently butcher the hell out of their bikes when adding mods.
Personally, I'd go for the '07. Mileage difference is negligible, and the owner appears to be on top of maintenance which is exactly what you want in a higher mileage bike. '07 introduced much better gauges, better swingarm, removable passenger pegs, better fuelling, better front brakes, improved front fairing, option of factory lower fairings. Unless you get a good deal on an '06, I would try to find an '07.
PS, sold my '06 FZ6 with 115k km for $2800 last spring. Had some pricey upgrades, but also had 115k km. $3200 for a stock '07 with half the mileage seems like a decent deal.