Your buckles are often referred to as suspender buckles however that's not quite true. There was a couple pf patents issued for those types to be used in suspenders but most were used as pants adjuster buckles and vest buckles. The buckles with 2 or 3 tines are generally considered civil war era. Yours is a 2 tine buckle of course and it should have something stamped on it, but not always. I think that yours will date from the mid 1850's to about the early 1870's. Good little finds, congrats.