Factual error: In the final game when Kit comes to bat, we get a quick glimpse of the right field foul line and there is an umpire standing on the line behind first base. In a previous shot, we see an umpire standing on the left field foul line behind third base. In the 1940s, three umpires were used for the majority of the games. With a runner on first base, as is the situation here, the umpire would position himself between first and second base. During the shots of Kit running the bases after she hit the ball, we see no other umpire between first and second base or anywhere near second base.
Factual error: While Racine did win the title the first year of the league, their opponent in the championship was Kenosha, not Rockford. Also, the series went 5 games, not 7.
Factual error: One of the stadium banners reads "Catch A Foul - Get A Kiss"; it is printed in the font Banco, which was created in 1951, eight years after the film is set.
Factual error: In the final inning of the last world series game, Dottie is seen catching a pop up as she falls into the dugout. You see the ball go into her glove and then, before she even hits the ground in the dugout, the ball has moved to her throwing hand. There is no way a catcher would even attempt to transfer the ball from their glove hand to their throwing hand while falling like that.
Factual error: In some scenes during the games, the sun is in the direction of right field shining towards home plate. In professional baseball games, this is never allowed due to the sun being in the batters eyes. Side note: This is why no ballpark in major leagues ever had home plate on the east side of stadiums when they were built.