Have 8 mile long surface for a waterline, contour labels seemed to be fine until I did the rebuild surface as prompted. Do not want to put all these individual and multiple contour labels back in again? Am I missing something like ADD labels or Import Label set? Maybe it is something in the initial creation and/or settings of the surface labels. I do have the surface label line appearance set to false.
 
Thanks!
David

Sounds like it might be a scale issue.  If you are viewing the lables through a view port make sure that your page setup is set to mm and not inches (providing you are metric)

Then you can check your drawing setup in the toolspace/settings tab to see what scale your model is set in.
Civil 3D Labels are annotative by nature, so if you are using a text style in that lable style that is annotative, you are making an annotative style annotative, which in my experience causes problems similar to the one you are describing.
 
If you are working in metric, make sure the contour lable style text height is set to something appropriate (1.5-2.0mm), and if that is correct then check your drawing scale (1:1000 should be fine for viewing lables in model space).  Then check and see if you can see your labels through the viewport or not, if you have corrected the problem in the model space, but can't see your lables in your viewport, then it's a simple page setup units issue.
 
Hope that helps! (even if it is a little late)