I noticed today my spark plug boot protectors are damp with oil. Only the boots coming off cylinder 1 and 3, with 1 being more damp than 3.

Are there any other causes for this beside the valve cover gasket?

I have a replacement VC gasket I'll be doing soon, but I want to prepare myself in advance if it could be something else. It's got 80000 miles on it. 03 park ave ultra