Re: How can I tell if my guitar has Locking Tremolo Studs?
Monsta, it's so that the trem stud is better anchored into the basswood. Basswood is a softer wood and over time, the trem studs can create and ovaling effect on the hole into which they're set. This affects tuning stability and causes problems. As I understand it, to counter this, a metal set screw is set into the wood and then a locking screw is set into that. The actual stud then goes in and is much more stable and locked in to enhance the longevity of the stud's hole and overall structural integrity.
To make adjustments to the stud, you'll have to first loosen the smaller set screw with an allen key down into the stud, then you'll be able to raise or lower the stud, then you'll want to re-tighten the set screw. I believe Ibanezrules has a picture showing the 3 parts that make up this formerly standard feature.