I should jolly well hope the nosegear is still in the air just at the point of touchdown!
I'm not aware of any reason that they wouldn't deploy all four - if they could do so safely. The only possibility I can think of is that there is a problem on the particularly aircraft with one of the outboard engines or reversers; in this case, to avoid the danger of assymetric reverse thrust, they would probably want to use the inboards (2 & 3) only?