When you said oil on threads, that's what I thought you meant. Did you have burnt oil residue at the bottom of the plug threads? I'm not sure how far below the well the threads reach...but I just read your first post again and see you were putting oil out the rear of the car...in just reading your recent post, I thought you were talking about just burning oil from vcg.
If you're still burning oil, putting out blue smoke, then I hope it's ccv. If not, then, you know, you probably have more serious issues.
I'd do ccv just to eliminate the chance it's head/head gasket. Had the car overheated when you had it? I'm sure PO wouldn't have told you it overheated, though you might look for evidence of that if the ccv doesn't work for you. Don't forget to either replace or clean guidetube when doing ccv.