Rambam gives the text of the Get in Hilchos Gerushin 4:12, and says that "all of Israel" customarily write it in this form. His text is indeed substantially similar to the ones you linked, although it's not word-for-word the same.
One difference that I see between Rambam's and Rosh's texts on the one hand, and what's used nowadays (at least in the gittin that I've seen), is that both Rambam and Rosh summarize any nicknames or cognomens of the parties to the get with a phrase such as וכל שום אחרן וחניכה (any other name or nickname), whereas in the ones I've seen, any such secondary names of the people or place are actually spelled out: "X, who/which is also known as Y..."