I have an Ibanez RG140 that (I believe) is from 1988. It looks like the whammy bar is missing and the original knobs have been swapped out. I'm just looking to restore it to original black knobs and bar, and think it's easily done with the knobs. I'm unsure, however, what type of tremolo arm it would take. I see some with screw arms and some without. Any idea how I can identify it without ordering the wrong one and having to return it? Any help is appreciated.