Nope. I'm the same. Never attempted it and had no desire to. I didn't even open the grenade packet when I first got it. I eventually did just to check it out but then I closed it right back up. I even removed all the loops to make the jacket less bulky. That's how certain I was that I would never want that pose.
I can see the value of this, but I would have to buy a second jacket to do it to. I hate doing permanent mods to my figures.