It should also be mentioned that OOTP has two historical modes. Recalc and classic.
Recalc turns off player development and uses player stats to produce the results (not sure if I explained that right). For example if Joe Blow had a bad year in 1947 he is likely to have a bad year in the game.
Classic mode keeps the development engine on. The total stat output is historically accurate but you cannot expect "Name" players to be studs as IRL or in Recalc. In fact it is likely that they will be duds. Some people do not like this mode. I do.
Maybe someone can explain Recalc better than I did.