Not really.

The only company I know which makes a measuring device is Specialized. Their Ass-o-meter is calibrated to their saddles. Unless you can find another saddle company that measures and sizes saddles exactly the same as Specialized, knowing what the Ass-o-meter recommends isn't going to help much. Even with Specialized saddles, it's hit-and-miss in my experience. I got measured, tried a bunch of saddles in the recommended size and none of them were comfortable. The only Specialized saddle that came close was a size smaller than the Ass-o-meter recommended!

In addition, knowing the width of your sit bones won't tell you a thing about what shape saddle you need. Does your saddle need a long nose, short nose, or no nose? Sit bone width doesn't help with that. Do you need a dead flat saddle, slightly curved, or radically curved? Again, sit bone width has no correlation as far as I can tell. Do you need a cut-out or not? Again, sit bone width doesn't help predict your preference.

The best way to buy a new saddle is to decide what you don't like about your current saddle, then look for something that's eliminates or minimizes that problem.