900 Transmission Blanker Plug Missing

I bought a 2017 Street Twin 900 a couple months ago with only 3000 miles. Recently I noticed that the plug/bolt shown in the attached picture is missing. The only info I can find is in the Haynes manual that I got with my bike which indicates that it is a "blanker plug" and that you must remove it to adjust how closely the gears mesh.

I can't find any info online to indicate a part number or a place to buy a new one. I would like to order a replacement ASAP, any info is greatly appreciated!