I was incorrect in saying that it's 3/32", but let me 'splain.... I've used a 3/32" Xcelite ball end wrench for years. Turns out the ball end has worn down to about 5/64", which is close enough to 2mm that it works well. So... 2mm it is. I got off my butt and actually tried a real, honest-to-God 2mm wrench and it fits; if a little loosely. 5/64" also fits. But a real, non-ball end 3/32" wrench? Nope. Too big. I think it's time for me to get a new blade for the handle. A 2mm blade. Mea Culpa, y'all. I goofed. Ken...
Well, you know best with your measuring device. I just went to my handy dandy allen wrench set (US & Metric) and found the one that fit my US L2K. It was #2 (which I assumed to be 2mm).
Obviously isn't the size for your bass. G&L used SAE (inches) parts through 2005, then switched to metric. Ken...