e1 is a rebrand of JG I think which is a clone of the CA so they will work.
There are only 2 makers on the market who make/made a .308 FAL and that's CA/E1(JG) and KA. only KA works in KA. If MAG mags 308 FAL mags they are probably for the KA so stick to the CA/JG/E1 mags.
I futz with V2s, V3s and V6s. I could be wrong... but probably, most likely not, as far as I know.