At one point young Paul is setting up a set incorrectly, with the Knight on a Bishop's square, he picks up a Bishop to place on a Knight's square. A quick cut shows all the pieces set-up correctly and Paul placing the piece on the correct square.
While taking place in the 1850's, for most of the scenes, a type of plastic chess set that first appeared around 1970 is used.
While taking place in the 1850's, Paul's mother refers to his memory perhaps being hereditary - "It may be in the genes as they say." The term "genes" was coined in 1909.