Flat belt or conveyor belt lacing has been around since the 1800’s and is still in use today. Your style with the staggered hooks is probably Clipper but there were different company’s making it like Armstrong and Alligator. We use mostly Alligator on our ranch for our flat belts. It’s also used extensively in the mining industry. Hard to put an age on your find find but being thin iron it’s hard to imagine it being much older then the 1920’s or 30’s or it may have rusted away in a wet environment.