I read about this. Evidently the chief Rabbi of Israel met with the pope and inquired about any ancient Jewish treasures that the Vatican may possess. They were offered a tour of the Vatican storage facilities, but the Vatican always maintained that they do not possess it.
I think it is wishful thinking on the Rabbi’s part. It would be great if it were recovered, but in reality, I think it no longer exists. The temple was destroyed in AD 70. Christianity was not permitted and elevated as a state religion by the Romans for at least another 250 years. It is doubtful that the Roman Empire, having disperesed the Jews throughout it’s Empire and having persecuted the Christians, would value such a treasure to keep it in tact I think that they melted the golden menorah down and turned it into items that they did find valuable.