so yup, it's an encrypted save indeed
JKSM is for modded 3DS, nothing to do with whether you mod your SD.
If anything, how does one mod their SD card? XD
well as long as it's the same 3DS (and hasn't been formatted since), it should work.
Also, to clarify (in case the question pops into your mind): installing CFW in-between won't matter.
All that matters is the 3DS is the same 3DS, and has not been reformatted since.
To explain: encrypted saves require the specific cart (if extracted from cart) and specifically the same 3DS (if encrypted save is taken from the 3DS) to be decrypted. So moving an encrypted save to another 3DS will render the save useless. Reformatting the 3DS also makes it as tho "it's another 3DS'.
So while decrypted saves will work on any other device or cart, encrypted saves are not so simple.
So as long as your 3DS is the same 3DS, and has not been reformatted since, it should work :3