I couldn't agree more with what's been said.
Directly to the original question, you can legally shoot an appendix-carried, laser-gripped, WML'd, mini-RDS'd pistol in Open Division of USPSA. Competitively, it will be a ridiculous hill to climb. Developmentally, if you try to climb that hill over and over and over and don't let yourself get frustrated, it is going to help light your skills on fire. Morally, if you personally are committed to competing as you carry, it's the only place where you have an equal place at the table and can shoot for official score and can roll how you want to roll.
USPSA Open truly is the original division where the pressure of competition is used to help determine which techniques and equipment work 'best.' Over decades, this has led to a number of significant equipment changes that have raised the bar of potential performance from equipment that has evolved to the point of factually being practical for defensive practitioners of the plain-clothes and uniformed varieties.