Wookieepedia says his armor is made from beskar AND durasteel. The wookiee scalp braids is old information long before Disney, I think it was in the old PC encylopaedia "Star Wars : Behind the Magic" that I first picked that up, and maybe also on the SWCCG cards that contained little factoids about stuff. A quick Google search shows pictures and snapshots from old encyclopaedia books, before the prequels even. In old books, he wasn't even called Boba Fett from birth, wasn't a clone, wasn't the son of a Jango Fett, had a very strong honor code, etc..
I recently read the "Skirata Clan" stories (now legends, non-canon by Disney) of Republic Commando/Imperial Commando and it mentions many times that ALL Mandalorian armors are made from beskar (Clone Wars/Rebels also mentions beskar as the base material, and The Mandalorian show obviously). This is also given as a reason as why the Empire wants to take over Mandalore because the mandalorians are one of the last threats thanks to their warrior prowess and their very resistant armor (and the Empire cannot easily duplicata the blacksmithing process, using beskar without the ancient knowledge bestowed to the smiths makes the armor very brittle).
There's been so many books/comics/video games/other media about Star Wars that it's probably best that they don't pick up every bit of information and try to squeeze it into canon.
Even if beskar is a retcon for Boba's armor (since I don't think beskar was a thing back in the 80's, the books at the time only mentioned durasteel for strong armors), it makes sense and is more coherent with what we've since learned about mandalorian culture from more recent sources (animated shows and Mando).