This was the form of SunTour V GT Luxe that was most familiar to British cyclists. I think it looked dandy, with the black background behind the branding and its black allen bolts.
I first came across this derailleur in 1977 (I think) when Raleigh introduced a bike called a Sun GT10XL, done out in matte black and gold (very John Player Special). It sported this gear, a 14 to 28 freewheel and a 42/52 SR cotterless aluminium chainset. As I remember it, this Japanese equipped Sun bike sold for £10 less than another Raleigh bike, a European equipped Carlton with a comparable frame, a steel Huret Svelto derailleur, a 14 to 24 freewheel and a weird steel cottered chainset that I remember as some kind of ‘half-step’ (perhaps 44/50). Needless to say, Raleigh did not sell many (any?) of the Carltons.
When it introduced the Sun, Raleigh was not sure that the British consumer would accept Japanese bicycle equipment - which is partly why it was all branded ‘Raleigh’. Their uncertainty did not last long.