I just got a Menace 4-14 FFP from a fellow member that I couldn't be more thrilled about. It has the "old style" knobs on it; I didn't know there was a difference. What is the dif? Also, the side focus knob doesn't have any distances marked on it, and I can't tell where I'm lining up the setting. Meaning there's no mark of any kind on the body to indicate where one lines up the dial for the desired setting. It doesn't really have settings, per se, but just a dial that looks like a volume control. Can this knob be swapped out for one with numbers?