But but but any energy transferred from the string to the body is lost tone. The string moves through the magnetic field of the pickup right? Any energy that is transferred away from the string motion is not moving through the magnetic field.
Now then, higher mass requires more energy to move. Absorbing less energy from the string. Leaving more timbre for the magnetic field to read.
If by vintage you mean a dark, slightly muted, warm tone then yes, losing a bunch of energy (or information) will do that. But not through a high mass bridge.