No they don't. Every study of buybacks has found that most guns turned in are very small caliber weapons (from bb guns to 22 caliber), non-functional guns (homemade shit sticks and broken guns), or guns of a type not common in gun/gang crime (revolvers, antiques, and shotguns).

Any hood smart enough to know to get rid of a hot gun is smart enough to know not to do so at the nearest police station.