It probably is. There definitely seem to be people best described as cis by default (would have been fine regardless of which gender they lived as), though there’s little evidence beyond self reported experiences (as opposed to the evidence for trans identity where cross sex hormones result in increased happiness and the very case study evidence for cis identity where loss or reversal of sexual traits are associated with development of gender dysphoria). We can also point to the reality that transness does appear to have scaled intensity, where some people hit the “transition or die” stage as teenagers, some hit it in varying other ages, and others never do but still feel transition was the correct course of action for their life.