This is, unfortunately incorrect, and if you do the research you will find that there is NaBO2 * 2 H2O, NaBO2 * 4 H2O, Na2B2O4 * 4 H2O and Na2B2O4 * 8 H2O
The first and the third in this list are the tetrahydrate, the second and the fourth are both the octohydrate, and tetrahydrate and octohydrate are indeed different in water content.
Actually, these are all the same chemical, but in different relationships and with different waters of hydration. With correct adjustment based on the Sodium content, you get the same results from all of them.
In water, at the same Sodium molar content, they form the same ions.