I agree that it isn't likely. I haven't seen one either. However, the order for eliminating the diamond on K frame target stocks was Change Order #1032, and it was issued on December 28, 1967. Since the 19-3 was introduced in 1967, it seems it is possible that a -3 could have shipped with diamond targets.I've never seen an early 19-3 with diamond center stocks, round or square.