That stud should still be available, try part # 90116-10149 or enter your frame # at
Japanese cars online catalogs you can prob figure out the bracket bolt there also if you find an image for the part.
Should be a 10mm stud either way so 3/8 drill bit max, but once you get close in size you might be able to get it with an ezout without snapping it. Lots of heat, lube, and the right size tap socket would be needed. Cobalt drill bits can handle a little more heat but even a basic hss bit should be fine as long as you use enough cutting oil, just no harbor freight bits. Some of the Chinese cobalt bits are more brittle than basic hss, and will snap easily which you def don't want, stick with US made bits or a big box brand. Drill at low-mid rpms for 10-15 seconds then re-oil. Get the right oil at Fastenal, or the plumbing aisle at home depot, motor oil isn't the same. If you go too close in drill bit sizing from one to the next the bit will sink too quickly and catch the edges and snap, see that happen a lot with new hires, so be aware of that and get ready to let off the trigger if it binds, and use a cordless drill if you have one.