That could just be because you have been used to the other stance. It's a new one on me right hand lead being called Orthadox but live and learn. When I did Karate we jast refered to it by which foot was forward. I.e. Left of right stance.
I'm weird in that I'm left handed, yet my right side has more power than my left. I think it's because I used to fence as a kid. As a result, I'm a lefty that fights orthodox. It lets me be really sneaky with my left though...
With snowboarding I ride regular, goofy always felt weird. I was actually right handed until after 1st grade because my kindergarten and 1st grade teachers at my religious school refused to let kids be left handed. I'm guessing that tweaked my brain's circuitry a little. I do some things left handed and some things right handed. I write, shoot, play pool, etc left handed but snowboard, swing a bat, box, and things like that from an orthodox stance. Any sport with a stance I generally do orthodox, aside from pool since my left hand has better fine motor skills.
No because your handedness doesn't determine stance, because people stand on their feet not their hands. Thats why it comes down to which of your feet are dominant. Therefore you are right hand AND right foot dominant.