To literally answer your question, yes it is a bit more complicated than just changing battery type on the inverter. Lucky, you have the Magnum 2812 because with the Advanced control panel you can make all the changes you want..
I just set one up for a guy with Battleborns. You will need to set the Charge Voltage, and set the charge to stop on Return Amps. Set the Return Amps value to 5% of the total amp hour capacity of the entire bank, Set the size of the battery bank. You will need to change the Low Battery Cutoff to around 11.5. And you will need to set the Float Voltage to 13.3 or 13.4.
My values are more conservative than what you will find on the BB site, but I err on longer battery life rather than eeking out the last amp.
99 Newell,Subie Outback toad