Yes, I sync all my music and voice memos with iTunes to my phone and PC. The two voice memos that I have that are just dates with no names are last on the list. I have one I titled rain and it is listed under the "R's" in my music. The one titled water running is under the "W's". I think there is an option within iTunes to sync voice memos. I hope this helps you.
I'm having the same problem. There's a bunch of old voice memos in the app that I can't play anymore (or share them). If I connect the iPhone to iTunes on a Mac I can only see the latest, playable, voice memos.