As of right now the only way i know to tell is there is an open surface is to look at it in wireframe and VISUALLY LOOK for incorrect geometry imported due to junk step files rom vendors.
THERE HAS TO BE A BETTER WAY!!!!!!
Can i select all quilts? Select surfaces? Nonmanifold? anything?
this is so painful.
You can use the Import Data Doctor to help find and fix these surfaces.
About Import DataDoctor in Creo Parametric
1.] to find out whether your model is solid, you can compute its weight
2.] to detect one-side edges in your model you can use Search Tool