When finding out Caesar left everything to Octavian, Marc Anthony calls Octavian Caesar's adopted son. This isn't possible, since Octavian's adoption was through Caesar's will (which was in fact legally impossible). More likely, Octavian would have been identified as Caesar's grand nephew.
The building where Marc Anthony reads Caesar's will is a Gallo-Roman temple. This is a type of temple which is only found in the Gaulish and Germanic provinces of the Roman Empire. No such building would have been found in Rome.