The USGI sling looks the best in my opinion, but it is not leather.

https://www.amazon.com/gp/aw/d/B072M6WBN4/ref=ox_sc_act_image_1?smid=A347PHAEBQKM53&psc=1

Measure your sling swivels to see if they fit, this is a 1 1/4 sling.