Soon after the wrestling match, the promoter is robbed at gunpoint by a criminal (Michael Papajohn, whose character name is later identified in Spider-Man 3 as Dennis Carradine) wielding a Beretta 92FS Inox. The robber pistol-whips the promoter with the Beretta and then later uses it to fatally wound Ben Parker (Cliff Robertson). He then uses the Beretta in a futile attempt to shoot at Peter Parker (Tobey Maguire) as he's being pursued. There are several continuity errors regarding this gun - as will be seen below.
Taurus PT92 AFS
During the car chase scene, when Peter Parker jumps on the roof of the car, the carjacker fires his pistol at him. Due to a continuity error, his Beretta 92FS Inox becomes a stainless Taurus PT92 AFS as he fires into the car roof. A close inspection of the gun in the screenshot below reveals that the pistol's trigger guard is the "flared" style of the Taurus PT92, rather than the "squared" style of the Beretta 92F.
Beretta 92FS
When N.Y.P.D. officers enter the abandoned building after the robber falls out of the window, they can be seen with Beretta 92FS pistols drawn.
Maverick 88
In the scene where the convenience store is robbed, one of the robbers can be seen brandishing a Maverick 88 with a high-capacity magazine tube.
Colt Trooper MkIII
In the scene where Spider-Man takes down the mugger, the mugger can be seen with a Colt Trooper MkIII, but soon has it taken from him by Spider-Man.
Heckler & Koch HK91A2
In the scene where Spider-Man foils the armored car robbery, two of the robbers are armed with Heckler & Koch HK91A2 assault rifles. These rifles were previously mis-identified as select-fire G3A3s, but a close inspection of the weapons from the screenshots below reveals that they have the non-pushpin lower receivers of the semi-auto-only HK91.
Glock 17
During the armored van robbery, another robber can be seen using a Glock 17, using it to pistol-whip the driver in the face. When the N.Y.P.D. officers enter the abandoned building earlier in the film, it appears several of them are also using Glock 17s as well as Beretta 92Fs, though it is too dark to get a good look at these pistols.
Remington 870
During the armored van robbery, one of the robbers can briefly be seen with a Remington 870 shotgun with synthetic furniture.
Smith & Wesson Model 629 Performance Center
During the armored van robbery, one of the robbers can be seen with a Smith & Wesson Model 629 Performance Center revolver, trying in vain to shoot Spider-Man with it before being knocked unconcious.
Walther PPK
When Spider-Man returns the body of the Green Goblin (Willem Dafoe) to the Osborne mansion, Harry Osborne (James Franco) catches him and pulls a Walther PPK from a desk drawer, though Spider-Man is gone by the time he gets it out.