Anecdotal, but I wouldn't expect it to count against you. I live in a traditionally lefty city (one of those "anarchist jurisdictions", heh), company culture skews left, etc., and I haven't observed any animus towards my ex-military coworkers, nor do they act like they expect any. Being in the military isn't in itself political. Your haircut or your accent will probably get you more unconscious biases (positive or negative, who knows) than that.