M60 Plugs Covered In Oil

Today I replaced both my front rotors, fixed my rear left window, got an oil change (well that was on the 1st actually) and replaced all eight spark plugs. While changing the plugs each and every one of them had oil on them and there was a small amount of oil in the surrounding area. I know this is a common failure of some gasket in there, anyone have anymore info on this? Thanks a lot! Not sure it's worth replacing since it's such a small amount of oil leaking into that area. I'm assuming all plugs being oiled means there is no misfire as there is no CEL or such. Also put on some top of the line Bosch Icon wiper blades. They are insanely incredible. They sell for 25.00/per blade but wow, the way they wipe just makes you want to keep wiping with them, it like shears the water away, hard to explain, highly recommend!