There is no doubt whatsoever regarding the authenticity of this site or place holding the holy relics.
And also Sahih ONE graded site are one and only as no other site in any part of the world take part in the claim in having anything to do with the narrative of the authentic site. As opposed to Sahih Multiple Primary which has one authentic site and many sites just for reverence.
Another Example: Cave of Hira & Jabla an-Nur (There is one and only Hira cave in the world and no other cave claims to be the ‘second cave of Hira’)
Also those places upon which the original construction was destroyed and something else was build over it over the period of time throughout history, those places also belongs to Sahih ONE grade because no matter what was build on the reamins of the old, the location is exact and authentic.
Example: Birthplace of Prophet Muhammad ﷺ. (Although here stands a library now, but the location is exact and authentic)
Coordinates: 31.780000, 35.237778