From 1978 - 1984 the grey bobbins were
ST Vintage (E) = 5.7 ohm avg
ST Vintage MkII (U) = 6.2 ohm avg
1983 - 1987
ST Vintage (V) = 5.7 ohm avg
ST Vintage MkII (VII) = 6.2 ohm avg - or even "IIV"
All have wax covered cloth wire of Black (ground) and white (live) and staggered pole pieces. These are for the ST models.
Early ST-42 and ST-45 models has a ceramic magnet pickup but this was stopped by 1980
For the SS models the bobbins were black with Black and Blue wires, levelled pole pieces and were 'H' Hot or 'S' Super. In 1983 these bobbins became grey and the letters were stamped onto the base, similar to the ST series.
In all, the 'E' series are the most sought after. As far as the 'T' model goes, I have not seen them, so they could be from 1990 and later models.