First of all, the band with the bolts in the side didn't have the slanted bolt at the bottom. Second, the slanted bolts go through the subrails at the front and this makes the nuts sit flat. Looks like someone has done some modifying on your cowl to make a later band work because the early bands are as hard to find as the brass ones. I found this out when I bought a cowl for a Tudor years ago and the cowl band didn't fit. I needed to replace the lowers and subrails so I made the cowl into a later one. The cowl band didn't have the correct curve so I ground the sides off of some 1/4 20 carriage bolts and slipped them into the band like yours are and pulled it in. It worked good but without looking, everyone said it wouldn't work but by changing both parts it did. You may have to replace the subrails to later style to get the job done correctly.