you can buy the kit on ebay pretty cheap....https://www.ebay.com/itm/Backrest-Si...19.m1438.l2649 HD used a harder to find thread pitch but I found them at ace hardware, I don't remember the size but you can take one of the short factory ones you remove with you an get the length you need. I found chrome spacers at home depot.

 

I stay corrected yes spring is outside the bracket. Thanks for sharing I guess now it is time to pay MoCo 🤔

 

Hard to measure the spacers for you due to the AUX lights. But the upper bolts are kind of special.



What you have appears to be a Nostalgic windshield.

Be warned as well that the springs are VERY close to the tank at full lock, check it carefully when you get it installed.