Spark plug condition

Hi all looking at other parts of ignition system pulled plugs all appear to be light tan in color, have NGK gr4gp plugs, I was surprised at the center electrode it is very narrow compared to other plugs I have seen I looked on line at photos of the NGK plugs and they look like mine so I think they are fine, the very last threads have some carbon on them but the electrode area is a nice tan color photo not the greatest