I think this may only be available from Amazon, sadly, but it does have some interesting stuff about the TV models.

I’m pretty certain that the GP colours weren’t used by Innocenti back in ‘63 so I very much doubt that any ochre paintwork would be original. There was an orange SX150 released in Italy in the late 60s but I have never seen or heard of a TV in this colour.
Early UK TV175s did have, as you say, versions with either yellow (more like a primrose yellow than ochre) or red panels, horn cast and front mudguard. There was also a version with a light blue horn cast and panels which may well have found its way to the UK. Italian TV175s, at this point, were all white, I believe.