Considering in Mexico is forbidden to own a gun with a caliber bigger than .22 the amount of different guns, many of them sub guns or assault rifles, they have is surprising, those also don't look like narco's guns as they usually use AR15/M16 style guns.
Civilians arming themselves would happen sooner or later, a big part of Mexico is no man's land, I wish them the best, but seeing the lack of training they seem to have I think narcos will fuck them up as soon as they decide to take them out.
The problem is also those groups becoming para military units, and then you have something like Colombia with many factions and the gov fighting each other.