If this goes to court it will very likely depend on the judge, but Frank was not posing an imminent threat to Boogie nor did Boogie have any reason to believe he would. Frank showed up empty handed and didn't even have a backpack or anything where he could conceal a weapon, rang the doorbell and was greeted with a firearm and immediate instruction to leave the property. You can't point a firearm at somebody because you 'feel' threatened, there has to be a real threat. He wanted to go there to talk, having to talk with somebody you don't like isn't reason enough to threaten their life.
As far as prior threats go, Frank has never said that he has any serious intention of physically harming Boogie. Unless there's something even worse on the newer interview, the worst shit I can recall from the last interview was him saying he'd sissify him and ride him around like a pig while making him squeal. He said it would be the "worst time of his life" but at no point said he was going to go there and physically assail him. It is all clearly high level trolling without serious intent.
I firmly believe that Frank would not have gone to his house had he not been goaded into it. Boogie was calling him a pussy and saying he wouldn't show up because he's a bitch and he's scared of going home in a body bag. Frank is not one to back down from any challenge or confrontation.