Hi Jim and Berk,
I think Evan S. Connell went into some detail on the variations between the nations and tribes in his book
Son of the morning star . Damned if I can find my copy to confirm this!
Regarding the use of iron arrow heads Joseph M. Marshall III in his book
The day the world ended at Little Bighorn first edition on Page 98
"Around 1840, the Lakota had fairly consistent access to iorn in the form of metal pots, the flat hoops from wooden barrels and wagon wheel rims. Some of that material was acquired in trade or after white people had discarded it. Iron was used by the Lakota to make knives, lance points, and arrowheads for hunting and warfare. The iron was either melted down or cut with a cold chisel or, if available, a hacksaw. The consistent availability of iron was a benefit to the Lakota because they could make knives and projectile points with it faster than ones from stone. (After 1850, the skill to make stone projectile points began to be a lost art.) ...
I have seen a few other articles on this topic and will look this week to see what else I can add.
All the Best
Jeff