Are those liners?

[Smoker]

I removed the head off of a 12 valve the other day and I could swear that the thing has liners in it. However, I have read and heard many conflicting reports about this subject. I have read on TDR that these are "throw-away" blocks with no liners that can not be re-used. I have talked to others who say that these blocks do not have liners but that they can be drilled to take liners if needed. Does anyone have a true answer on the subject?