Hey! Welcome to Tnet.
It would be of help to mention the area in which you found your buckles. No buckle expert here but if you give a bit more information I think someone can help you.
Cool finds and good luck out there.
If found in a Civil War campsite or battle site, a high possibility it had soldier usage. Only 100% for certain soldier usage if you found it deep in a trash or hut pit. That's about as far as you'll get it to being Civil War buckles.
If they were found in a group, they could be a discarded harness of some sort. I’d say it would be tough to link it directly to any military use, but who knows. Cool as hell anyway
All I can tell you is that they are iron harness buckles which may or may not be from the Civil War era. There is no way to tell if they are Civil War related or not.