Dealing with partner companies and even clients can be difficult which is one reason we tend to stick with the same partners.
We have seen studies that show that partner data exchange man-hours can be a huge chunk of total project man-hours. These often get buried and hidden in your total project costs.
There is nothing about Civil 3D drawings that make this significantly more difficult than other Autodesk dwg based applications.
A good set of styles will allow you to Export to to raw ACAD format and get acceptable results.
DWF output may be even better.
Then they cannot mess with anything...
However, if your partner insists on using something back more than two dwg format changes (about five years), then we suggest you start looking for another partner/client and or educate them about the benefits of model based design.
A little knowledge might save you both significant time, effort, and money.