That definitely seems to be an error, but there apparently have been cases of curved FAL mags existing, and apparently some guy filed down a Bren .308 mag to fit in the magwell of the FAL, to great success.
For comparison, their canon weapons are Toriko normally uses an AK-101 and Sorawo normally carries a Makarov pistol she got from Toriko. The AK-101 was acquired in the other side. They are the weapons most commonly depicted with them in cover art.
