Julius Caesar is referenced as a tribune, however this would be impossible as the office of tribune was specifically created for the plebeian class. Caesar was a patrician (aristocracy), and therefore ineligible for the office of tribune, no matter how much Crassus bribed on Caesar's behalf.
In reality, Oenomaus was Gallic (from modern-day France, like Crixus), not of African descent as depicted as the series. See Orosius' Histories.
In several episodes the use of the letter U, for example under the bust that Batiatus made for Spartacus, was seen. The letter U in Latin wasn't used in place of V as consonant until the Middle ages.
The characters frequently address Batiatus, among others, using the form of address "Dominus" (Lord). In Latin, the proper form of this word used when addressing an individual would be in the vocative case, and should instead be "Domine."