Unlikely - the company I worked for out of college was considered "unhackable" by top hackers (we hired 3 notable ones at the time). Not that it couldn't be hacked, but we used really old OS's and processors I learned about in the history of computing class. In short, it was a lack of information about them that made it really hard.
How does that apply here? Yes, governments may devote resources to hacking other governments weapons, but "street" hackers are unlikely to do this.