you can get SAC and DAC engines (single, dual annular chambers) there is some thing in the part number that signifies a DAC engine. it is possible to mix (have on either wing) but there should be a notive in the cockpit to inform crew. can remember how many fuel nozzles there were but there was still only 2 igniters.
they are a pain in the backside to boroscope too((DAC's that is)