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Mid 1957 showed major changes for the Precision. Sometime after July the headstock became larger, now resembling the Stratocaster headstock shape. During the year the Kluson tuners large screws changed from slot head to phillips head on most basses. During the year the pickup changed from single coil to a two piece black bobbin split humbucker with raised pole magnets, now including a metal grounding plate underneath the pickups. The one piece white pickguard changed to a laminated 10 screw gold adonized aluminum pickguard. The pickguard shape also changed, no longer covering the top horn but extending down so it replaced the pots assembly plate. The Stackpole potentiometers and Switchcraft input jack were now directly mounted onto the metal pickguard. The chrome pickup cover and bridge cover with foam string mute took on more rounded shapes. The thumb rest was still under the G string, but was now manufactured in black plastic with two fastening screws. The knobs changed from dome shaped to a flatter top. Also around mid year, string grommets and their body holes were discontinued as the strings no longer passed through the body. The two saddle metal bridge changed, now including four finely threaded individual saddles. The string ends now fastened to the bridgeplate, which had only slighty rounded corners.

Other 1957 Precision bass characteristics: spaghetti logo with no patent numbers applied on top of the finish, one piece maple neck with skunk stripe and phillips head screw truss rod adjustment, black dot fret markers, neck butt pencil date, fifth hole on neck butt for hanging while painting, no neck pocket paint stick, body nail holes (for painting/drying), pickup cavity pencil date, white rectangular tone capacitor with blue stripe, cloth wiring, ground wire route underneath bridge, two tone sunburst finish, brown tweed case with red "Koylon" interior or brown vinyl gigbag.

Serial numbers ranged from roughly 17000 to 024000, although there are many overlapping exceptions. For more precise dating cross reference the serial number with the instrument's neck butt, body date and pot codes. Some serial numbers were preceded by a dash (-).