Original / Authentic Military Issue Combat Rosary from WWI or WWII

It may be a long shot but I've been researching these for a while and I've read that many survived to this day and are now collectable. I want to find one for my husband before his next deployment. I don't expect it to be cheap. I am looking for where I could go about buying one and/or verifying one's authenticity. Any ideas? Or thoughts on how to find one that has been through military action but wasn't necessarily military issue.