"If a Temple is to be built, we need to know if this really is the site, and not just something accepted as the site."
Though this is not a small matter, don't trip over it. The Jews have known exactly where the Temple should be built for a long long time.
Which Jews? There is dispute on the matter.
There is noting in the Bible that syas it has to be built on the exact spot as the Dome of the Rock...it just merely needs to be close by!