In the one set of interviews for a Pro/E designer position at a previous company, we gave the candidates a typical part to model and create a drawing. This put one of the candidates out of the running as he did not have a clue how to model the part.
The questions I would ask would depend on what types of parts were being designed. I would not cover ISDX if the company only used simple machined parts. If the company does consumer products with organic shapes you can expect ISDX as well as questions regarding designing molded parts etc.
Look up the company and get an idea of what they do.
Infotech Aerospace Services