nah, think you're wrong. just go to Youtube and search "saints asha love", or "saints rescue asha" ect. EVERY video of the mission distinctly shows your toon crouching (male or female). and it only makes sense considering the mission. it's a parody of stealth games like MGS. you're using a silenced rifle for 1 hit head shots, Asha crouches too. doesn't make sense to dual. the game locks you into a crouch til about 3/4 through that mission, then you can stand again. but i'm guessing since the guns the mission equips you with starts you out dual wielding, then the game locks you into that dual wield pose.
it wasn't a big deal. i just removed the dual wieldable flag from any rifle named "Storm" in the weapons.xtbl. then the mission played as intended, after which i added the flags back.
edit: thinking about it, the mission might correct itself on it's own, because not too far in, you are forced to go into air vents so you'd have to crouch, or i would think there'd be some rather bad glitches lol. so this might correct itself, and all my typing could be for naught lol. i corrected things before i got to the vents so not sure. either way, i still think that 1 single rifle better fits the stealth parody of the mission