Shroud attaching hardware?

The U nuts they used there are quite small as stated above. They fit the offset in the flange.
The bolts were about 1 inch long with kep washers. Some claim those are special bolts. I dont know for sure. Maybe there head is under standard size or the kep washer is under oe over standard diameter and/or thickness. If you have to have exact, I've seen them on ebay before.