by JimN » 17 May 2010, 12:59
Hi, Rune,
All contemporary pictures of The Shadows with Jet in the line-up show that he used his Precision Basses with both the pickup-cover and bridge-cover in place. That was normal at the time. The fashion for removing those metal accessories on the Precision and Jazz basses didn't come about until later in the 1960s and the covers were seen as part of the design and the "look".
With the bridge-cover in place, it wouid not be possible to palm-mute the strings at the bridge (though maybe some limited muting would be possible by placing the heel of the hand against the strings between the two covers). Instead, it seems likely that Jet achieved the Kon-Tiki sound by tone-shaping on the amp and percussive use of the plectrum. The only additional damping which might have been in use would have been the piece of neoprene glued to the inside of the bridge-cover as a permanently-on damper making contact with the strings at the bridge point. This was discontinued on later editions of the Precision, but it was there on early examples.
Hope this helps,
JN