Most of the time, the Maaskantje police officers are carrying the Walther P5 as a standard weapon.
Unidentified M1911A1 variant
After his discharge the Maaskantje police officer steals at least two pistols from the gun locker. He hands out one to a prisoner he tries to recruit for his crusade, but the prisoner decides to kill himself rather than help a cop. The gun appears to be some kind of customized M1911A1 variant with several external parts as sights etc. missing.
Police snipers on the a roof, waiting for the New Kids to show up. The Maaskantje officer on the left is using an WWII era model M1 Carbine with 30-round magazine (or possibly an automatic M2 carbine, but no fire selector switch is possible to tell for sure).
Remington M40 Sniper Rifle
Police snipers on the a roof, waiting for the New Kids to show up. The reinforcement officer on the left is keeping a Remington M40 Sniper Rifle at the ready.
Take-away owner Henk Snackbar (Ruud Matthijssen) receives an M1A1 Thompson from Richard to protect his business and Manuela's children. He later uses it in an ambush.
In the background during the scene in the weapon stash, an MG15 machine gun in an anti-aircraft application can be seen.
Miscellaneous
Pump action shotgun
Also in the weapon stash we see Gerrie (Tim Haars) carrying a pump action shotgun. The brand/model cannot be identified.
M72 LAW
Gerrie (Tim Haars) uses a M72 LAW to take out an approaching police car. There is a inconsistency in the movie, since he fires the same M72 LAW two times. In real life it's a single-use weapon.