You bet they were.  THOUSANDS of years ago, too. 

Those prints were called "chops".  My uncle, who was a professor of Chinese languages and history (before he retired from Toronto university a while back), and I were recently having a discussion about this very topic - and it was mentioned in an article I read somewhere just today!  Soooooo, I thought I'd look it up and post whatever I could find.  Well, there's LOTS of stuff about this subject but most of it is pretty convoluted, so I decided on this link to share because I think it'll be the easiest to understand.

https://www.ancientpages.com/2016/03/04/fascinating-ancient-history-of-fingerprints/i

If you keep scrolling down, you'll find lots of interesting things about past history the world over.