Frankly, even in the late seventies that ugly thing was already on his Tbird. As the bass is a sixties TB, the original bridge was probably discarded due to intonation problems - he just didn't have your good Badbird bridge to fix it back then!
Uwe
In 1973, Martin's Bird was still sunburst and had the sixties bridge plus a maple repair headstock (the bass had been broken on a Mott the Hoople tour).
Still unchanged in 1975:
Come 1976 it had been refinned white (and the neck repair from Mott days - the bass was bestowed to him by Overend Watts - improved), but still retained the original bridge.
But come 1977, he must have seen a pic of you Scott, imitation is the sincerest form of flattery:
Over time, the ugly Badass had an ill effect on Martin's mind:
Under the influence, he did some horrible things:
But old age wised him up again:
