To my, admittedly very poor eye, it looks different. Moreover, Princess Marina died in August 1968 and I am under the impression that the snake tiara was sold to pay inheritance taxes. Of course I might be thoroughly confused.
Could there be a Kent tiara with which we are unfamiliar? Possibly. I have one media report which suggests that Princess Marina was given a tiara as a wedding present by the Duke of Kent. I know nothing about this jewel or what it might have looked like.
I realise that many will dismiss the report in the Sunday Times as fanciful; however, in light of Franck's recent find about the previously unknown tiara of Princess Alice, Duchess of Gloucester, I am inclined to keep an open mind. The Duke of Kent may have given his bride a tiara with which we are unfamiliar. Re Franck's find see http://members2.boardhost.com/royal-jewels/thread/1467580524.html