Chevelle Camaro Nova OEM 396 427 454 big block exhaust manifolds 1968 1969 1970

Description

Item is a pair of OEM GM exhaust manifolds for a Chevelle / Nova / Camaro.  These were removed from a '69 Chevelle 396 years ago and believed to be original.  These particular castings were used in 1967 to 1970 on vehicles listed above with 396 / 427 / 454 engines.
Left side manifold:  3909879  Date code:  A 23 9 (? the "9" is a little less clear than the other numbers)
Right side manifold:  3916178  Date code:  L 7 8
None of the numbers are crystal clear, so please see photos.
These are "smog" A.I.R. system manifolds.  Someone has plugged the A.I.R. ports and cut the plugs flush with the manifold surface.  As pictures show, 7 out of 8 plugs are brass, so these should remove easily with extractors (the 8th plug looks to be iron / steel - see photos).
Exhaust pipe studs in good condition, and appear to be original.  Manifolds are pitted (see photos - typical for 50 year old manifolds), but no signs of cracks or other damage.
Item sold as-is.  Payment shall be via PayPal.