Good luck. let us know if they're OK.
Some have reported the fit isn't great. You may have to do some fitting.
My understanding is the small outer bolts were a change starting in 1979.
There was another change in design - which I don't recall but I think its mid 70s.

OMIX had them new with the heat stove.
However my experience with OMIX is they don't spend a lot of effort on QC.
I decided to rebuild mine.

The exhaust manifold bolts used since late 1969 early 70 are unique. Its was an early change for this generation AMC V-8 and there was service bulletin to dealerships.