Colour of plugs looks ok, but current fuels don't show this effect as clearly and defined as they seemed to in the past.
You can make an adjustment to the plug heat range though by going upward one number for NGK plugs. What this will do is shorten the heat pathway from the centre electrode to the plug outer material and so reduce the tip temperature, it should show as a darker colour when running and give more margin of safety to the conditions it's running in the combustion chamber.
Unless you've done anything differently than looking at the plugs after a run out they won't be showing that specific area of jetting to give you an accurate reading for the main jet size.
To do that, you'd have to get it fully warmed and then get it pulling hard in 3rd gear with the throttle full wide open, a long uphill or partly holding a little brake while you do it to make it fully loaded and working on the main jet calibration. 5 to 10 secs then cut clutch throttle and ignition, then check the plug colour to see what you've got (ordinarily called a plug chop) and assess the affect that main jet size is having.
If it pulls cleanly and runs without flat spot through full rev range it must be very close. You'd not expect that size engine with std intake to run a bigger main jet.
