This came in the box with a Canadian Enfield in the early 90's:
The buckle is flat metal. The leather looks to be pebbled with indentations running along the outside edges. Here's a couple more picsThe metal looks like it's from a U.S. Garand sling or is copied from one. It's the leather thats interesting. Are there any markings on it? Is the buckle made of flat steel or from wire? It's hard to tell from the photo.