Most 170 grain bullets are made for the .30-30 and are flat points or RN's. Lapua 170 grain Naturalis bullets are an RN too. Not the best bullet for a .300 WSM.
However, work up a load with a 168 grain bullet. Then, when you have the most accurate load, load a few(two full mags worth) of the over priced bullets and see if there's any change. You load for the bullet weight, not who made 'em.
Having the word 'Lapua' on anything costs more. Just like having Weatherby or Cadillac on anything.