This from GT site.

Pro Hunter
Pro Hunter shafts are guaranteed to the most consistent graphite hunting arrows in the world. Each arrow is tested to a straightness tolerance of +/-.001” and weight tolerance of one grain per dozen to make them the most accurate wrapped graphite arrow ever built. Pro Hunter shafts come standard with GT Series nock and inserts, and are available in Black or Advantage Timber finishes.

XT Hunter

The award winning XT Hunter Series arrows continue to set the standard for straightness, consistency and durability. Each dozen XT Hunter Series arrows are now laser inspected for straightness and then hand sorted for a guaranteed weigh tolerance of +/- 2 grains per dozen. XT Hunter arrows feature a straightness tolerance of +/-.003”, come standard with new GT Series nocks and inserts and are available in Black or Advantage Timber finishes.

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I dont think what the "Pro Shop" guy told you is exactly accurate.

Altho I dont use either of these 2 arrows for hunting I do use the GT Ultra Light Pro'sfor target and have found the advertised specs to be spot on with only 2 arrows out of 6 dozen out of spec which GT sent me replacements.