If I recall correctly, hi points are also blowback weapons, which means you're going to get more noise out of the ejection port than you would with a browning type action.
I'll also second the question of why you'd do that to a hi point. There are other hosts that are MUCH better at handiling a suppressor than a blowback 9mm. The expense of a second threaded barrel for another gun will likely be close to what you spend to get the hi point threaded anyway. I understand wanting to suppress something different (which is why I'm working on finding someone to thread a P64 for my micro 9mm can) but if you're looking for a cheap way into the suppressor game, I fear it's going to be a good bit more expensive than you were hoping and I don't think you'll be happy with the results.
And if you do wind up suppressing it, remember that if you have a fixed barrel you need a fixed mount, and if you have a tilting barrel you need a booster on the can.