I have a pair of 2899879 (right side) BB exhaust manifolds

The date codes are 8229 and 1770, I am trying to find a better matching date for my left side exhaust manifold. Looking for a late Oct or very early November 1969 RH exhaust that I could maybe swap with someone. Both of my exhaust affords are in great shape, no cracks or pitting, heat riser valve works fine. Your swap would have to be in as good as shape. Attached are pics.

Thanks

8229.jpg

1770.jpg