It is , and I am big on end times prophecy and know that all the prepartions for the rebuilding of the Temple are complete. They have all the supplies the high priests need to carry out the rituals. With these authentic artifacts it makes the case even stronger to start rebuilding. Although the Ark of the Covenant would probably be needed.
This book was an entertaining read, but the author's theories must be taken with a very large grain of salt.
In the book, Mr. Hancock claims that the Ark is in Axum, Ethiopia.
The thing is (as I understand it), the implements for the Temple can't be duplicated, so the implements that have been built ahead of time and stored in museums aren't kosher for use in the Temple. They will have to be built especially for use in the Temple and for no other purpose, which has to wait until Mashiach arrives and begins the process.
Then there's the problem of the vast majority of all Jews (all but the very youngest) being temei' metim (defiled by contact with dead bodies), a condition that can only be remedied by the mei niddah (made from the ashes of the Red Heifer), and these have to be mixed with the ashes of the previous heifer. It's a very complicated maze. Then there's the problem of having to have children raised in absolute purity in order to acquire water from the pool of Shiloach, for which no provision has yet been made (so far as I know).
The only thing we can be sure of is that G-d will be able to remove all these many difficulties so that the Holy Temple will indeed be rebuilt correctly in accordance to all the laws. This accomplishment will be a miraculous evidence that Mashiach has arrived and the Kingdom of G-d is here.