For anyone interested, I achieved the expected behavior by adding the RooCmdArg AutoBinned(0) to my generate command.
so
RooDataSet* genDS = theHistPdf.generate(myVars, NumEvents(10), Verbose(1));
became
RooDataSet* genDS = theHistPdf.generate(myVars, AutoBinned(0), NumEvents(10), Verbose(1));
I am still unsure as to why the previous method gave me the results it did, perhaps it returned a RooDataHist and the bin centers were located in the same spot in memory where the point values would have been for a RooHistPdf? Regardless, turning AutoBinned off gave me what I wanted.