I need information about the screw or bolt in the red-marked area of the photo where the mount connects to the light (e.g., length, thickness, thread).
Do you have the mount itself ?
If you do... use a caliper (if you have one at home) to measure and as for the thread, either its coarse or fine. You can tell be how close they are together.
Other option is take it to HomeDepo and there should be a thread count and size template you can measure. Lastly, I think its easier if you just email AI for something specific like this.