KAOS THE CAT, if you don't plan on changing the sight much once the gun is sighted-in, there's no reason that I can see to have bush-snagging Target Knobs on a hunting rifle. I have Williams "Fool Proof" receiver sights mounted on several of my hunting rifles, sans the target knobs, and have never missed them.
Receiver sights being used for target competition, when the sights are being adjusted often to address different distances to the target, accommodating varying wind conditions, using a diversity of ammunition/bullet weights, etc., is, of course, a different matter altogether.