Oh come on, you can't be serious. Your mother saw exactly the same golden lotus stand as every British author described it, do you honestly believe that the relic upon that lotus stand was a "fake" from 1815 to 1972?
she mentioned it was a golden lotus with small gold threads [& some other mentioned in last comments], didn't mention stand is identical to the image. and you're acting like there can't be another golden lotus stand in the world. stand in the image could be different to the one shown to the public. there could be another one when they store it. who knows how many stands they have.
regarding 1815 to 1972, hell yes, as I believe there a real high possibility. Just imagine yourself in the position, it's your entire job [more likely purpose of your life] to protect it. would you trust the once who destroyed country, and the religion it self? I don't think anyone would.
I think the best thing you could do is, go there and see yourself, then say it to us. I'll believe you. no problem.
without dragging this discussion for too long, IMHO, the one shown in the image is a casing, not the real tooth.
if it is the real one that they honestly have, I personally don't believe it's the real tooth of buddha or any human in that matter.