Buckles with tongues fixed in the center before the late 19th century(?)

[invent4hir]

All, please educate me. Every so often I see a post on TNet saying buckles with a tongue fixed in the center didn't appear before the late 19th - early 20th century. Yet, the attachment shows such buckles in 3 different books with that feature before the late 19th century - in some cases hundreds of years before. So, are these books incorrect?

Note: Because this isn't a "What is it?" topic I originally posted this in the Buckles forum. I re-posted here because it didn't get any responses there and usually the topic comes up here.