Well, well, that's something new I've learnt!
Like [almost] everyone else in the UK, I'd always known that the 'V-sign' was a rudely contemptuous gesticulation ... God knows, I have used it many times myself! ... an unspoken way of conveying the message: "Stuff YOU, mate!". Being of a certain age, I was equally aware that it had been famously attributed to much-publicised photographs of a cigar-smoking Winston Churchill holding up the third and fourth fingers of his (I think) right hand in a V-shaped formation to denote 'Victory in Europe' towards the end of the last World War.
But apart from THAT ... ???Anyway, thanks Nigel for your informative post.