[sammyg2]

If you try and re-torque a nut that has rust or lack of lubrication on the threads you will not over tighten it, you will under tighten it. If the friction is more than it should be you will twist it the same as when it was new, it just won't turn or it won't turn enough to duplicate the specified stretch.

In order to achieve the proper stretch on the old stud you would have to go way past the specified torque. if you don't do that re-torquing a stud without fresh, clean, lubricated threads is a waste of time except to prove the stud isn't already snapped off or ready to snap. It would be useful to diagnose a possible problem but not to make sure you have the correct tension on the head studs.
If the stud is that close to snapping off, it will do it by itself very soon. Do you want to know know or later?

On studs that see elevated temperatures over prolonged periods the best anti-sieze lubricant available IMO is milk of magnesia from the drug store. just paint it on. it will last and lubricate longer and better than any anti-sieze I've tried, and we've tried just about all of them on the market where I work.

It is all we use on $1million pieces of equipment that run at 1300 degrees F. for 5 years continuously between overhauls.

Some anti-sieze products actually cause corrosion embrittlment on exotic metals. Lead based and copper based are the worst, nickel isn't as bad.