Oil in intake ports?

Fuel evaporates. Oil doesn't. So if there's oil up there, while it might be from reversion, the oil is the problem - not the fuel.
In terms of the cam - there should be little to no reversion. It's not big by any standards. But there could be sealing issues with the valve seats - which might be indicated by a compression test or even better a leakdown. Leakdown will also confirm condition of the rings. The valve seals might be marginal too - but they won't create crankcase pressure to blow out the end seals of the intake.

Sorry - reversion is the reflection of intake charge from the open intake valve. At low rpm there is little inertia to keep the mixture moving in the port so as the piston stops at TDC and begins to come up, but the valve is still open, some of the mixture can be squeezed back into the intake port above the valve. Bigger cams and valve jobs with great low lift flow are susceptable to reversion at low rpm because larger cams generally involve the intake valve being held open longer.