340 exhaust manifolds

[three two barrels]

After reading through all 11 pages in the exhaust section and learning a lot, I would like to thank everyone that made a comment, it was very informative.

I've posted pictures of a set of 340 manifolds with the L2 date codes, can anyone prove that these are date coded for 1970 and does the position of the screw head mean anything.

The drivers side manifold has no pentastar or casting number while the 1969 manifold has both, any significance about that?

Thanks