BJ8 Manifold, how many brass nuts?

[AUSMHLY]

Working on a friends 66 BJ8. I noticed his has (10) brass nuts on the exhaust and inlet manifold. Photo attached.
My engine has (5) brass nuts and (5) shorter steel nuts. Photo attached.
On my engine, the steel nuts are on shorter studs. However I noticed that my friends brass nuts are also on shorter studs.

Which is correct. All nuts should be brass?

 

[dcarlg]

I think studs for the exhaust manifold have brass nuts.

 

[steveg]

10 tall-form brass nuts all together on upper exhaust manifolds - on every exhaust-only stud and the two siamesed exhaust/intake studs.

Manifold-to-downpipe nuts are normal-length brass nuts. Balance of manifold-only nuts steel.

Source: Moss catalog page, "Manifolds 100-6, 3000 (6 port, twin carb)"