04 6 V-6 Oil in spark plug help!

[boahx]

I'm looking to buy this 2004 mazda 6 but the owner says it has oil in the spark plug chamber & doesn't start. I'm wondering what issues this might cause it?

I'm thinking worn out valve cover gasket or piston rings are fried? (stash)
If someone can shine abit more light on this would be great thx..

 

[wannabe]

yeah i'd guess valve cover gasket