Are these correct 842 heads?

[iluv69s]

ebay listing http://cgi.ebay.com/ebaymotors/GM-NOS-Al...=item2c534af4d0 (http://cgi.ebay.com/ebaymotors/GM-NOS-Aluminum-Heads-ZL1-COPO-Yenko-L88-L89-3919842_W0QQitemZ190375982288QQcmdZViewItemQQptZMo tors_Car_Truck_Parts_Accessories?hash=item2c534af4 d0)

is that where they dated original heads?? and did they make theses heads that early?

[69 Post Sedan]

Those are over the counter heads. I have been trying to figure out how the casting dates work on those.

[69 Post Sedan]

Here is another set of these OTC heads.

http://i300.photobucket.com/albums/nn2/brkyard/Parts/BjDcwtwBWkKGrHqUH-D0Es-YhG0HyBLR682.jpg

This is an original 842 casting date.

http://i300.photobucket.com/albums/nn2/brkyard/Parts/COPO-CleanedHeadsCastingDate-1.jpg