I didn't do it!!!

        Imagin my surprise when I went under my "new" 84 Westfalia to change
the oil and found a one inch bolt sticking out of the oil plug area.  a wing
nut device ther was holding a rubber stopper in place.  This thing holds the
life blood of the engine in.  I wiggled it and it fel off in my hand!  My
oil pan was already there but what if this had happened on the road!!!
        I replaced the rubber stopper and it seems to be holding.  I ordered
a new bolt from the dealer but I suspect that the inner threads may be
stripped.  I'll try a new bolt but then what?  I have a good shadetree
mechanic near buy but what is the best fix for this?  Help.

Eric