Yes, my Whirlpool 21 cuft EnergyStar draws a little less than 1 amp AC or a measured 8 amps DC...96 watts on a 40 percent duty cycle. It came within 1/2" height of fitting perfectly. My biggest mistake was not replacing my NoCold 1200 sooner because of the fear of boondocking. Two additional batteries is all that's needed to make it match our other battery needs.
You can find my DIY installation in the Feb 2016 link above. I installed a 1000 watt PSW inverter for the refrigerator and satellite/TiVo unit and it stays on 24/7 when not on shore power. I used child safety locks to hold the doors shut.
While I never measured how many amps the two heating elements in a 1200 draws, I do not doubt the OP's 12amps. My electric bill this past winter was $20 less than previous years now that I have a residential refrigerator.,
