No - would not have expected them to do so.
However, B did an extra part of a lap, but when C grade finished they were not all that far behind B grade, which I thought was pretty good when I know a heap of the C graders who were driving the bunch in that first lap to catch B grade would have been pretty tired.
Always good to give a rabbit to chase - the HDCC crits, where A grade got a 10 second start on B grade, were always good races.