Having done a few long trips through Europe on my Harley-Davidson Road King Classic, I had learnt that not having locks on the standard leather panniers is a real pain. This means that I could not leave anything of value in the saddlebags.
I had heard that you could buy locks for these saddlebags and I had previously set out to find some on the web. I found they were available in the USA and had bought a set from the Lock It company (http://www.lockitt.com/). Today, I fitted them. It took a couple of hours and was relatively straightforward. They were quite expensive ($180), but in the long run, I suspect they will be more than worth the money.