That spark plug looks like its been in the engine for 12000 miles.
It would be wet if it was fouling. It looks to be neither fuel, nor oil. Most likely carbon
Build up.
If the engine eats oil enough to foul a plug, it'd smoke as well I think.
And unless you've either did a leak down test ( preferred) or a compression test to determine overall consistency between cylinders, I'd think twice before pulling anything apart.