I don't know any Nissan, or import really, that uses stretch bolts. You are allowed to reuse them. As long as they aren't corroded, pitted, rusted, whatever, I reuse them. If they are, I find a used one in my stash that isn't. Never had this happen. Man, I thought exhaust studs were bad, must suck to have to take the head off again and get a new head gasket.