I'm writing a novel in which the main characters are tracking down a necromantic cult in modern-day Alexandria that originated in Roman Egypt. One of the clues to the location of a shrine involves taking a certain number of steps which the characters realize are equivalent to the number of bones in the human body. I was going to blithely put 206, but it occurred to me to wonder how many bones would a physician in 2nd-century Alexandria be aware of? Would they know about the tiny bones of the inner ear or, say, the hyoid bone? Thanks in advance, historians!
The most prolific Roman (As in Rome: the Empire, not Rome: the City, he was located in Pergamon and was writing in Greek at the time with the Latin texts being translations of the original Greek) writing on medicine in general and skeletons in particular was named Galen. He notably mistakenly claimed the lower Jawbone to in fact be two seperate bones and his texts were so influential that they were still being used until 1537 when Andreus Vessalius proved him to be incorrect on the aforementioned Jawbone thing as just one example of a larger text he was compiling to push forward the argument that slavishly adhering to the classical texts was not to our benefit and we must learn to progress the fields by making our own observations.
The most relevant of Galen's texts for you is Galen (A.D.130-201), Peri osteon tois eisagomenois, usually known by the Latin translation of its title, De ossibus ad tirones "On bones for beginners",
Annoyingly he doesn't seem to at any point list how many bones the skeleton has in total, but instead chapter by chapter describes the bones of each part of the skeleton and their qualities so you have to go through and add them all up as you go, which I apologise for not finding the time to do for you. Especially since he ends his text by clearly mentioning that he has not described all the bones but instead says
"It seems to me that this is all beginners need know about bones and the construction of the skeleton, and that there is no need to discuss now any small bone found in other parts, as in the heart, larynx and nose, and in some of the digits which are called sesamoids, or anything else of the kind."
Therefore even if Galens the leading expert at the time did profess to know how many bones the body had, he didn't deign to share this with us as he only discussed what he thought were the important ones to talk about in this text and if he ever did write a followup text on bones for the intermediate or advanced reader it did not survive for us to read today.
I don't know the tone of your Novel, but if for your writings you want a cute little factoid that is inspired by history but in a very pop-history way I would use 207 and at some point have the characters remark that Galens thought the lower jawbone was two seperate bones in a manner that feels somewhat reminiscent to me of this Indiana Jones scene, it could end up being as fun and cool as Indiana Jones, but will also probably not end up being much more historical than Indiana Jones is. What is likely to be a more historical answer is that they didn't know or didn't care exactly how many bones there were.
If you wish to read the bones and his descriptions of them yourself an accessible English translation can be found here.