It will certainly do no harm to retension the head bolts, even if the gasket wrapper says it's not needed.
Make sure that you do it with the engine COLD. I have deveolped a habbit of first loosening each bolt in turn & then retensioning it. This overcomes any problems of stiction & a more accurate reading is obtained. This is more important in a higher mileage engine.

It needs to be loosened only a little, so don't bother taking it right out, unless you forgot to lube it properly the first time.