Is the FAS2040 Battery the same as FAS2020?

I've been told they are the same, but as i do have them both, i checked on FAS2020 the code is 271-00010 and on the FAS2040 the code is 271-00024.

I need to be sure, because i need to replace the FAS2040 battery and i am only able to find the part #271-00010 (FAS2020).

A friend told me it is supposed to be the same, but i need to be sure.

Thanks in advance.