Yes they did, there were quite a few cavalry charges during the September campaign (somewhere around 20 documented ones), the majority of them were performed with sabers, there was one or two that involved lances. There were also fighting between mounted Polish and German cavalry on a few occasions. They were occurred during the entire campaign, from the very first battles to the final battle. Most often the charges were quite successful, dispersing unaware enemy infantry, capturing artillery, attacking unsuspecting columns of "soft skin" vehicles and such. Though the role of the cavalry was primarily to act as modern dragoons, and they were used as such predominantly compared to the bold cavalry charges.
It's worth noting that German cavalry too was trained to charge at the enemy if the situation was right (though I don't know if they actually did this during the September campaign).
As Anatoli pointed out, the Poles charged at easy, unsuspecting targets, especially camped infantry, which tends to panic in such situations (who wouldn't?).
Unfortunately, there is a myth about Polish cavalry attacking German AFVs with sabres and lances - this is a piece of German propaganda, which was later adapted by the Polish communists, and now is repeated by some who really believe in it.
As for the minis, they're lovely.