Professional historians? No, but they were supposed to be telling the truth, and if they contradict each other, they can hardly both be telling the truth.
I did find some good info on the subject though. Apparently Census’ were held every eight years, Herod is now believed to have died more around 1 B.C. than 4 B.C., and also, no precise dating of the time period is really possible anyway because so many calendars were in use that to claim any one historian is an authority is very unreliable.