In Scene Two Mac mentions that the pin has been pulled out of the grenade but when they walk into the cafeteria it's clear that the pin is still in the grenade.
Phil's stockbroker friend "EF" is implied to be E.F. Hutton, co-founder of what was then the E.F. Hutton Group brokerage, who died in 1962.
Flo tells the mugger that January 3, 1943 was a Monday. That date actually fell on a Sunday.
Dan needs money to buy a hot stock, and Bull agrees to loan him $5,000 dollars, pulling a wad of cash from his pocket and counting off five bills, meaning each was a $1,000 bill. This type of bill was discontinued in 1969 and never was in general circulation, so it would be very unlikely that Bull would have them.
Christine tells the mugger that she was his lawyer, as well as his mugging victim. As a victim of the crime, she would have to remove herself from representing him as a matter of conflict of interest.