The first question anyone will ask is WHY do you need to remanufacture bolt heads Bow?
The second is this. IF....... and I seriously question this......... IF your friends are matallurgical engineers (or metallurgists but you didn't quite say that.....), then they will EASILY be able to establish EXCACTLY what the material spec of the bolt head is. That is a simpe fact.
Even if they are just simply good engineers, they will EASILY be able to use a shadowgraph - or even a simple steel ruler to establish what the thread form is.
Something just doesn't ring true here. And here's another point to ponder. If you want to make an extended bolt head to, say extend the life of an un-C.H.S.able rifle, then don't bother. The body is worn out/through the induction hardened surface of the locking shoulder

Just my 2c's worth. Any thoughts JM, Bruce from Oz and Son?