Scarface (1983) - 4 questions

Question: Does anyone know the approximate timeline of the movie? I noticed shortly after Tony kills Frank (I think it was the scene when he meets with his lawyer), he and Manny walk near a billboard advertising the "all-new 1984 Corvette". The '84 Corvette went into production in March 1983, so I don't want to call it a mistake in case it is factually correct.

Answer: Early 80's is about right. That billboard wouldn't constitute a mistake either way. That same billboard could still be visible years after the car was released.

Question: In the scene where Scarface shoots Frank and then Mel, right before he shoots Mel, The dialog goes as follows: Mel- you can't shoot a cop. Tony- Who said you were a cop? Mel- Wait a minute, I can fix this. This is said as though Tony wasn't supposed to know Mel was a cop, but did anyway. Even though Tony already knew this as evidenced by the fact that Tony said to Mel earlier, "How do I know you're the last pig I'm going to have to grease?" Why would this dialog take place if Scarface already knew?

Answer: Mel's statement that "you can't shoot a cop" is not said as if Tony does not know, but merely out of shock that Tony would consider killing him. He assumed, incorrectly, that Tony would not kill him because of the consequences associated with murdering a policeman. However, Tony is a Cuban refugee with a bad temper, and with nothing to lose, so he does in fact kill Mel, and continues his rise to power.

Question: Do we ever find out how, when or why Tony got his scar? Or is it of no significance?

Answer: No, he never reveals how he got the scar.

Question: Can anyone please tell me what Tony says to Rebenga as he is stabbing him in the prison camp? It sort of sounds like, "I'm gonna pay you f***." But that doesn't make sense.

Answer: He said, "From a friend you fu**ed."