Joe Jackson's gun is 100% legit -- TMZ has learned, Michael Jackson's dad is fully-licensed to carry a concealed weapon in the State of Nevada ... this according to a rep for the Las Vegas Metro Police.
The rep tells TMZ, Joe was issued a CCW permit in 2010 by the LVMPD -- allowing him to carry a concealed handgun on his person anywhere in Nevada. The permit expires in 2015.
As we reported, Joe showed off the concealed weapon at a recent event in Vegas, and claimed he doesn't leave home without it.
FYI -- Nevada's what they call an "open carry" state -- meaning anyone (over 21) can literally walk down the street with a handgun strapped to his or her body, as long as it's exposed.
With Joe's permit, he's allowed to keep it inside his jacket.
Bottom line ... don't mess with Joe.