Heya, recently got my hands on a new 3ds that came with the fire emblem fates cover plates for the equivalent of 76 bucks, the thing is, and i already knew for advance, that it had problems with the charge, by that i mean, it lasts like one hour and maybe some bit more playing, and after looking a bit through internet, it seems that the battery it has its an alternative one, because, from what the seller told me, the original battery is swollen, and im looking to get one, maybe from facebook marketplace or something like that

The problem is, when looking to buy one, how can i see the differences between an original and an alternative battery?

EDIT: forgot to add the thing with the stylus, the one that came with the console, although it fits well, the stylus tends to be a bit loose, dont know if its something to do with the console itself, or if i should just get a new stylus to replace it