Purchase in the gift shop at the National Tower at Gettysburg, PA. The tower was a private attraction that offered amazing views of the surrounding countryside and parts of the battlefield. It was torn down.
This toy Napoleon has a brass barrel and a metal carriage (composition unknown). It is marked MFCO c1/1 on the bottom, which probably means Michael Falk & Co. and then the model number. According to this site they are still being made, but not by Falk. I'm guessing you might be able to find them for sale at battlefield park gift shops in addition to the internet.
I'm pretty sure I also bought a pin of the III Corps, 1st Division badge (a red lozenge) in the same gift shop. III Corps at Gettysburg was commanded by General Dan Sickles. He defied orders and moved III Corps forward of its defensive position creating a salient in the Union line. His troops were badly mauled and Sickles' own leg was blown off (by a cannon if I'm not mistaken). His leg wound up in an Army medical museum and Sickles visited it after the war. Sickles was well connected politically and was able (years later) to get himself awarded a medal of honor. Did anyone say hubris?
Historians debate to this day whether Sickles actions (which cost many lives) may have actually had some benefit at Gettysburg. Some say it may have drawn Confederate troops away from attacking the Union flank (which was attacked and famously repulsed repeated charges). There are other arguments for and against Sickles actions. But it was a good thing there were additional Union Corps to fill in the gap Sickles left.