David Starsky (Ben Stiller) carries a custom Colt Commander Series 70 with Novak sights, a stainless barrel, a stainless guide rod, ambidextrous safety, and a beavertail grip safety (some of these feattures were not available in 1974, when the film takes place) as his sidearm in the film.
Colt Python
Ken "Hutch" Hutchinson (Owen Wilson) is seen using a 4" Colt Python at the begining of the film while undercover as a robber. One of the Bay City Police officers who arrests these robbers is also seen with a 4" Python. For the rest of the film, Hutch uses a 6" Colt Python as his sidearm.
Walther PPK/S
Reese Feldman (Vince Vaughn) takes a Walther PPK/S with a stainless finish (unlike a regular PPK) fitted with a sound suppressor out of his cooler to kill one of his men on his yacht. This gun is anachronistic for 1974.
Walther PPK
Insetad of his stainless PPK/S seen earlier in the film, Feldman holds a polished nickel plated Walther PPK to Hutch's (Owen Wilson) neck after he is busted selling drugs during his fund raiser. He fires several shots into the air before running out and driving away in his car.
Smith & Wesson Model 19 Snub
One of Huggy Bear's (Snoop Dogg) men is seen with a snub nose Smith & Wesson Model 19, drawing it when Starsky (Ben Stiller) accidentally shoots the tail off of Huggy Bear's iguana. Starsky is also seen using a snub nose Model 19 in an attempt to intimidate Chau (George Cheung) by playing a game of russian roullete with him. Chau notices how he "inconspicously" drops the round into his sleeve. But Chau also notices how the round miraculously falls back into the gun, which Starsky fails to realize. Luckily Hutch stops Starsky before he accidentally shoots himself.
M1911A1
One of Huggy Bear's (Snoop Dogg) men keeps an M1911A1 stuffed in his pants "Mexican Carried". The gun's polished chrome finish and ivory grips make it resemble the gun carried by John Travolta in Pulp Fiction.
Remington 700
Chau (George Cheung) takes shots at Starsky and Hutch with a wood stock Remington 700 sniper rifle, only succeeding in shooting up Starsky's Gran Torino before driving away.
Smith & Wesson Model 10
One of the robbers with Hutch is seen briefly using a Smith & Wesson Model 10 revolver, although the gun is replaced with a Webley MK IV later.
Webley MK IV
One of the robbers is seen with a Webley MK IV when arrested by the BCPD police. During the robbery, it was a Smith & Wesson Model 10.
Smith & Wesson Model 64
Both a robber and a BCPD officer are seen armed with stainless steel Smith & Wesson Model 64 revolvers at the begining of the film. Later, Reese Feldman's (Vince Vaughn) henchmen Kevin (Jason Bateman) is seen holding a Model 64 on the police in the crowd during the fundraiser when Feldman takes Hutch hostage.