Unfortunately, the dynamics of these situations tend to not favor the gun owner who "displays" his/her weapon. If the other party reports the act it boils down to a "He said, she said" standoff. Since it is easier to identify displaying a firearm a criminal act than driving a truck stupidly, the lady in this story ended up with the short end of the stick.
The fact the troopers didn't arrest her indicates they really didn't know what to do but took the easy way out by confiscating her pistol. That way they can't be put on the hook if she drives on down the road with her pistol and "assaults" another truck driver.
I imagine, if there is no evidence to the contrary, the county prosecutor will decline to file any charges. Especially if the troopers failed to get the truck driver's name and address.
I think she'll eventually get her pistol back, but it might be faster to get another one.
She would have come out better if she slammed on her brakes to avoid a little black dog and sued the driver for whiplash injury.