It is directly corroborated by the report that the Exif did visit at least once:
Although the Exif have avoided making explicit statements, this is not the first time they have come into contact with us humans, and it is highly likely that they have interfered with us several times. The historical instances of interference that our research team has been able to surmise from their communications include the founder of Buddhism, Siddhartha Gautama, and the Pythagorean cult, which is said to have laid the foundations of modern mathematics.
Both of these peoples are said to have used advanced mathematics to determine the reality of the world, which cannot be perceived by humans through their natural language senses, around the 5th century BC, and sought to achieve self-liberation and harmony with the world by arriving at the truth. Their methods and ideas are very similar to those of the Exif, and it is thought that they somehow passed on their methods and ideas to humanity, even if not directly. Original mathematics did not reject the mysticism we use today, but was thought to be a science that explored a more spiritual, non-physical dimension far removed from the dimension of reality, as studied by ancient people and valued by the Exif.
And by Godzilla: Monster Apocalypse, which implies that the banker in the Kamacuras attack is practicing a form of Exif religion when he signs the cross and prays towards the Christian god (I think? I may be biased here, forgive me) in 1999.
However, there is spotty evidence to say that “Gematron” was what directly inspired “Gemataria”. The report above cites “around 5th century BC”, while the first known use of Hebrew gemataria was in the 8th century, 300 years earlier. Pythagoreanism was founded in the 6th century, which is much closer.
Here’s my opinion on the matter: In the Godzilla Anime Timeline, It’s likely that the Exif inspired isopsephy and notgemataria. Isopsephy would then go on to inspire gemataria (opposite to real life), and the Exif would finally adopt the term “Gematron” after it was presented to them. Of course, we must reconcile this theory with a damning quote from Monster Apocalypse:
Unlike the Bilusaludo, the Exif people had actually been in contact with earthlings for a very long time, perhaps since ancient times. Isn't it more than just a coincidence that the Gematria calculation method used by the Exif has the same name as the ancient Hebrew numerology? It was likely that the ancients tried to imitate the Exif's wisdom. They had long been with us, perhaps even among the great figures and prophets mentioned in the myths and faiths of various nations.
Mind you, this is NOT one of the people in the report, this is a quote from a UN official. It’s entirely possible that this official did not know how Gematron calculation got its name, and assumed it the naming to be “backwards”. However, it also states that he became an Exif convert in 2034, while the contact report was made on September 7th, 2035. (Also, the people in the report are implied to be directly brainwashed by the Exif, which makes this whole ordeal worse…)
TLDR: Yes…? No...? Maybe? Contradicting evidence? A lot of words to just say “dunno”.
Sorry if anything looks off, I only skimmed Godzilla: Monster Apocalypse and I don’t know a lot about numerology. Dx