Nope, not at all, it will work fine. Just think, you have 2 "12 volt chargers" under the hood already, mounted to the engine!! [^] With the way the system is designed in the CUCV, you can wire a small charger to each battery, directly. Look carefully at how they are wired, and you will see...
Frame to - of battery one, + of battery one, supplies 12v to the majority of the truck (lights, etc). + of battery one, also connects to - of battery two. and + of battery two provides 24v to the starting system.
basically, if you connect anything to the frame, then to battery one +, you get 12v, if you connect anything to the frame, then to battery two + you get 24v.
Now here is the cool part!!! :hop: If you have an isolated device (like the battery chargers) and you connect positive of it to battery two + and negative to battery two -, you can have 12v there as well, BUT :nono: you must make absolute sure that it cant 'short' to the frame.
Hope this all makes sense, but for sure, you can use 2 12v battery chargers wired individually to each battery.