Was the 1.030 FG a one-time reading or did it truly finish there? Did you take the reading with a hydrometer or a refractometer?
The fact that your bottles are "nicely carbed" means that it could possibly have been done, even though a 1.030 is awfully high. What yeast did you use and what was your ferment temp?
The few kit bocks I've tasted seemed to all be a little bit on the sweet side. If it's drinkable, drink it. Invited some friends who prefer sweet beers to share it with you.