Technically, they are header studs and nuts. Some will come out easily, some will not. some will break during removal of the old heads. Hopefully THAT is a minimal circumstance, but it does happen occasionally. Unless your truck is pretty new, or you are REALLY lucky, chances are that some will not be reusable. To avoid delay, just get a new set that will cover the installation.
It sounds like a lot of money, as I suppose you are getting them from a stealership? But really, the insurance that new header studs & nuts will provide is worth its weight in gold. That said, I'm sure you could get some studs/nuts from the local auto parts store that would be cheaper. Online, I'm seeing Dorman and Hooker sets of 10 priced less than $10. You could go for ARP locking studs for about half the cost you stated.
We also have some site vendors you could check out for the parts you will need. They usually offer discounts.