These were around in the early 90's and not vintage in the sense they were used as an official display. I had a couple that I acquired at one of Jasons shows, think it was Cheshunt, in a trade. The chap told me the were part of a petrol brand promotion and had no reason to doubt him at the time.With no internet, there was no way of double checking stuff like this and SW collecting was still in it's infancy so new stuff was being discovered almost weekly.
However, these things started popping up all over the place, literally dozens of them at various shows all over the country. It was clear these were churned out recently. I don't know for sure if these were intended to scam or just something that were manufactured as test pieces that were never used. I've never seen them as part of an official display and have seen them in different colours, although this is the first one I've seen for a few years.
The odd thing is the size and scale of it - that Vader sculpture was massive in order to vac form at that size. Such a strange thing to pass off as original.
They're certainly an oddity.