The DLC weapon will be located at the START or first checkpoint of each location. They're placed on a special stand or table.

Add the Thompson submachine gun wz.28 to your equipment!
In the mid of the 1920s Poland purchased about 100 Thompson wz. 1921/3 (wz. 1928) for the National Police. In 1936 16 pieces were handed over for use in the Border Protection Corps. The weapon was used in the 1939 defensive war and later in partisan battle.